SIST EN IEC 61788-17:2021

SLOVENSKI STANDARD
SIST EN IEC 61788-17:2021
01-september-2021
Nadomešča:
SIST EN 61788-17:2013
Superprevodnost - 17. del: Meritve elektronskih karakteristik - Krajevno kritična
tokovna gostota in njena porazdelitev po površinsko obširnih razsežnih
superprevodnih plasteh (IEC 61788-17:2021)
Superconductivity - Part 17: Electronic characteristic measurements - Local critical
current density and its distribution in large-area superconducting films (IEC 61788-
17:2021)
Supraleitfähigkeit - Teil 17: Messungen der elektronischen Charakteristik - Lokale
kritische Stromdichte und deren Verteilung in großflächigen supraleitenden Schichten
(IEC 61788-17:2021)
Supraconductivité - Partie 17: Mesures de caractéristiques électroniques - Densité de
courant critique local et sa distribution dans les films supraconducteurs de grande
surface (IEC 61788-17:2021)
Ta slovenski standard je istoveten z: EN IEC 61788-17:2021
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
SIST EN IEC 61788-17:2021 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 61788-17:2021

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SIST EN IEC 61788-17:2021


EUROPEAN STANDARD EN IEC 61788-17

NORME EUROPÉENNE

EUROPÄISCHE NORM
June 2021
ICS 17.220.20; 29.050 Supersedes EN 61788-17:2013 and all of its
amendments and corrigenda (if any)
English Version
Superconductivity - Part 17: Electronic characteristic
measurements - Local critical current density and its distribution
in large-area superconducting films
(IEC 61788-17:2021)
Supraconductivité - Partie 17: Mesures de caractéristiques Supraleitfähigkeit - Teil 17: Messungen der elektronischen
électroniques - Densité de courant critique local et sa Charakteristik - Lokale kritische Stromdichte und deren
distribution dans les films supraconducteurs de grande Verteilung in großflächigen supraleitenden Schichten
surface (IEC 61788-17:2021)
(IEC 61788-17:2021)
This European Standard was approved by CENELEC on 2021-06-02. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.


European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN IEC 61788-17:2021 E

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SIST EN IEC 61788-17:2021
EN IEC 61788-17:2021 (E)
European foreword
The text of document 90/462/FDIS, future edition 2 of IEC 61788-17, prepared by IEC/TC 90
"Superconductivity" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
EN IEC 61788-17:2021.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2022-03-02
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2024-06-02
document have to be withdrawn
This document supersedes EN 61788-17:2013 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 61788-17:2021 was approved by CENELEC as a European
Standard without any modification.
2

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SIST EN IEC 61788-17:2021
EN IEC 61788-17:2021 (E)
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-815 - International Electrotechnical Vocabulary - - -
Part 815: Superconductivity

3

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SIST EN IEC 61788-17:2021




IEC 61788-17

®


Edition 2.0 2021-04




INTERNATIONAL



STANDARD








colour

inside










Superconductivity –

Part 17: Electronic characteristic measurements – Local critical current density

and its distribution in large-area superconducting films

























INTERNATIONAL

ELECTROTECHNICAL


COMMISSION





ICS 17.220.20; 29.050 ISBN 978-2-8322-9663-9




  Warning! Make sure that you obtained this publication from an authorized distributor.


® Registered trademark of the International Electrotechnical Commission

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SIST EN IEC 61788-17:2021
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CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Requirements . 9
5 Apparatus . 10
5.1 Measurement equipment . 10
5.2 Components for inductive measurements . 11
6 Measurement procedure . 12
6.1 General . 12
6.2 Determination of the experimental coil coefficient . 12
6.3 Measurement of J in sample films. 16
c
6.4 Measurement of J with only one frequency . 16
c
6.5 Examples of the theoretical and experimental coil coefficients . 17
7 Uncertainty in the test method . 18
7.1 Major sources of systematic effects that affect the U measurement . 18
3
7.2 Effect of deviation from the prescribed value in the coil-to-film distance . 19
7.3 Uncertainty in the experimental coil coefficient and the obtained J . 20
c
7.4 Effects of the film edge . 20
7.5 Specimen protection . 20
8 Test report . 21
8.1 Identification of test specimen . 21
8.2 Report of J values . 21
c
8.3 Report of test conditions . 21
Annex A (informative) Additional information relating to Clauses 1 to 8 . 22
A.1 Comments on other methods for measuring the local J of large-area HTS
c
films . 22
A.2 Requirements . 22
A.3 Theory of the third-harmonic voltage generation . 23
A.4 Calculation of the induced electric fields . 24
A.5 Theoretical coil coefficient k and experimental coil coefficient k′ . 25
A.6 Scaling of the U –I curves and the constant-inductance criterion to
3 0
determine I . 25
th
A.7 Effects of reversible flux motion . 27
Annex B (informative) Optional measurement systems . 28
B.1 Overview. 28
B.2 Harmonic noises arising from the power source and their reduction . 29
Annex C (informative) Evaluation of the uncertainty . 33
C.1 Evaluation of the uncertainty in the experimental coil coefficient . 33
C.2 Uncertainty in the calculation of induced electric fields. 34
C.3 Experimental results on the effect of the deviation of the coil-to-film distance . 35

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C.4 Examples of the Type-A uncertainties of J and n-values, originating from
c
the experimental uncertainty in the U measurement . 35
3
C.5 Evaluation of the uncertainty in the obtained J . 36
c
C.6 Experimental results that reveal the effect of the film edge . 37
Bibliography . 39

Figure 1 – Diagram for an electric circuit used for inductive J measurement
c

of HTS films . 10
Figure 2 – Illustration showing techniques to press the sample coil to HTS films . 11
Figure 3 – Example of a calibration wafer used to determine the coil coefficient . 12
Figure 4 – Illustration of the sample coil and the magnetic field during measurement . 13
Figure 5 – Illustration of the sample coil and its magnetic field generation . 14
Figure 6 – E-J characteristics measured by a transport method and the U inductive
3
method . 16
Figure 7 – Illustration of coils 1 and 3 in Table 2 . 17
Figure 8 – The coil-factor function F(r) = 2H /I calculated for the three coils. 18
0 0
Figure 9 – The coil-to-film distance Z dependence of the theoretical coil coefficient k . 19
1
Figure A.1 – Illustration of the sample coil and the magnetic field during measurement . 24
Figure A.2 – U and U /I plotted against I in a YBCO thin film measured in applied
3 3 0 0
DC magnetic fields, and the scaling observed when normalized by I (insets) . 26
th
Figure A.3 – Example of the normalized third-harmonic voltages (U /fI ) measured
3 0

with various frequencies . 26
Figure B.1 – Schematic diagram for the variable-RL-cancel circuit . 29
Figure B.2 – Diagram for an electrical circuit used for the two-coil method . 29
Figure B.3 – Harmonic noises arising from the power source . 30
Figure B.4 – Noise reduction using a cancel coil with a superconducting film . 30
Figure B.5 – Normalized harmonic noises (U /fI ) arising from the power source . 31
3 0
Figure B.6 – Normalized noise voltages after the reduction using a cancel coil with a
superconducting film . 31
Figure B.7 – Normalized noise voltages after the reduction using a cancel coil without
a superconducting film . 32
Figure B.8 – Normalized noise voltages with the two-coil system shown in Figure B.2 . 32
Figure C.1 – Effect of the coil position against a superconducting thin film on the

measured J values . 38
c


Table 1 – Specifications and theoretical coil coefficients k of sample coils . 14
Table 2 – Specifications and coil coefficients of typical sample coils . 17
Table C.1 – Uncertainty budget table for the experimental coil coefficient k′ . 34
Table C.2 – Examples of repeated measurements of J and n-values . 36
c

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

SUPERCONDUCTIVITY –

Part 17: Electronic characteristic measurements –
Local critical current density and its distribution
in large-area superconducting films

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 61788-17 has been prepared by IEC technical committee 90: Superconductivity. It is an
International Standard.
This second edition cancels and replaces the first edition published in 2013. This edition
constitutes a technical revision.
This edition includes the following a significant technical change with respect to the previous
edition:
a) A simple method to calculate theoretical coil coefficient k is described in 6.2.1.

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SIST EN IEC 61788-17:2021
IEC 61788-17:2021 © IEC 2021 – 5 –
The text of this International Standard is based on the following documents:
FDIS Report on voting
90/462/FDIS 90/464/RVD

Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all the parts of the IEC 61788 series, published under the general title Superconductivity,
can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

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INTRODUCTION
Over thirty years after their discovery in 1986, high-temperature superconductors are now
finding their way into products and technologies that will revolutionize information transmission,
transportation, and energy. Among them, high-temperature superconducting (HTS) microwave
filters, which exploit the extremely low surface resistance of superconductors, have already
been commercialized. They have two major advantages over conventional non-superconducting
filters, namely: low insertion loss (low noise characteristics) and high frequency selectivity
1
(sharp cut) [1] . These advantages enable a reduced number of base stations, improved speech
quality, more efficient use of frequency bandwidths, and reduced unnecessary radio wave noise.
Large-area superconducting thin films have been developed for use in microwave devices [2].
They are also considered for use in emerging superconducting power devices, such as resistive-
type superconducting fault-current limiters (SFCLs) [3] [4] [5], superconducting fault detectors
used for superconductor-triggered fault current limiters [6] [7] and persistent-current switches
used for persistent-current HTS magnets [8] [9]. The critical current density J is one of the key
c
parameters that describe the quality of large-area HTS films. Nondestructive, AC inductive
methods are widely used to measure J and its distribution for large-area HTS films [10] [11]
c
cos(3ωt + θ) is the most
[12] [13], among which the method utilizing third-harmonic voltages U
3
popular [10] [11], where ω, t and θ denote the angular frequency, time, and initial phase,
respectively. However, these conventional methods are not accurate because they have not
considered the electric-field E criterion of the J measurement [14] [15] and sometimes use an
c
inappropriate criterion to determine the threshold current I from which J is calculated [16]. A
th c
conventional method can obtain J values that differ from the accurate values by 10 % to 20 %
c
[15]. It is thus important to establish standard test methods to precisely measure the local
critical current density and its distribution, to which all involved in the HTS filter industry can
refer for quality control of the HTS films. Background knowledge on the inductive J
c
measurements of HTS thin films is summarized in Annex A.
In these inductive methods, AC magnetic fields are generated with AC currents I cosωt in a
0
small coil mounted just above the film, and J is calculated from the threshold coil current I ,
c th
at which full penetration of the magnetic field to the film is achieved [17]. For the inductive
method using third-harmonic voltages U , U is measured as a function of I , and the I is
3 3 0 th
determined as the coil current I at which U starts to emerge. The induced electric fields E in
0 3
the superconducting film at I = I , which are proportional to the frequency f of the AC current,
0 th
can be estimated by a simple Bean model [14]. A standard method has been proposed to
precisely measure J with an electric-field criterion by detecting U and obtaining the n-value
c 3
(index of the power-law E-J characteristics) by measuring I precisely at various frequencies
th
[14] [15] [18] [19]. This method not only obtains precise J values, but also facilitates the
c
detection of degraded parts in inhomogeneous specimens, because the decline of n-value is
more noticeable than the decrease of J in such parts [15]. It is noted that this standard method
c
is excellent for assessing homogeneity in large-area HTS films, although the relevant parameter
for designing microwave devices is not J , but the surface resistance. For application of large-
c
area superconducting thin films to SFCLs, knowledge on J distribution is vital, because J
c c
distribution significantly affects quench distribution in SFCLs during faults.
The International Electrotechnical Commission (IEC) draws attention to the fact that it is claimed
that compliance with this document may involve the use of a patent. IEC takes no position
concerning the evidence, validity, and scope of this patent right.
___________
1
 Numbers in square brackets refer to the Bibliography.

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IEC 61788-17:2021 © IEC 2021 – 7 –
The holder of this patent right has assured IEC that s/he is willing to negotiate licences under
reasonable and non-discriminatory terms and conditions with applicants throughout the world.
In this respect, the statement of the holder of this patent right is registered with IEC. Information
may be obtained from the patent database available at http://patents.iec.ch.
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights other than those in the patent database. IEC shall not be held
responsible for identifying any or all such patent rights.

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SUPERCONDUCTIVITY –

Part 17: Electronic characteristic measurements –
Local critical current density and its distribution
in large-area superconducting films



1 Scope
This part of IEC 61788 specifies the measurements of the local critical current density (J ) and
c
its distribution in large-area high-temperature superconducting (HTS) films by an inductive
method using third-harmonic voltages. The most important consideration for precise
measurements is to determine J at liquid nitrogen temperatures by an electric-field criterion
c
and obtain current-voltage characteristics from its frequency dependence. Although it is
possible to measure J in applied DC magnetic fields [20] [21], the scope of this document is
c
limited to the measurement without DC magnetic fields.
This technique intrinsically measures the critical sheet current that is the product of J and the
c
film thickness d. The range and measurement resolution for J d of HTS films are as follows.
c
– J d: from 200 A/m to 32 kA/m (based on results, not limitation).
c
– Measurement resolution: 100 A/m (based on results, not limitation).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60050-815, International Electrotechnical Vocabulary – Part 815: Superconductivity
(available at )
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-815 apply,
some of which are repeated here for convenience.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
critical current
I
c
maximum direct current that can be regarded as flowing without resistance practically
Note 1 to entry: I is a function of magnetic field strength, temperature and strain.
c
[SOURCE: IEC 60050-815:2015, 815-12-01]

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IEC 61788-17:2021 © IEC 2021 – 9 –
3.2
critical current criterion
I criterion
c
criterion to determine the critical current, I , based on the electric field strength, E, or the
c
resistivity, ρ
-14
Note 1 to entry: E = 10 µV/m or E = 100 µV/m is often used as electric field criterion, and ρ = 10 Ω · m or
-13
ρ = 10 Ω · m is often used as resistivity criterion.
[SOURCE: IEC 60050-815:2015, 815-12-02]
3.3
critical current density
J
c
electric current density at the critical current using either the cross-section of the whole
conductor (overall) or of the non-stabilizer part of the conductor if there is a stabilizer
Note 1 to entry: The overall current density is called engineering current density (symbol: J ).
e
[SOURCE: IEC 60050-815:2015, 815-12-03]
3.4
transport critical current density
J
ct
critical current density obtained by a resistivity or a voltage measurement
[SOURCE: IEC 60050-815:2015, 815-12-04]
3.5
n-value
exponent obtained in a specific range of electric field strength or resistivity
n
when the voltage/current U (I) curve is approximated by the equation
UI∝
[
...