Issue title: 12th International Workshop on 1&2
Dimensional Magnetic Measurement and Testing (2012)
Guest editors: Helmut Pfützner, Georgi Shilyashki and Franz Hofbauer
Article type: Research Article
Authors: Fiorillo, F.a; * | Beatrice, C.a | Son, D.b | Ahlers, H.c | Groessinger, R.d | Albertini, F.e | Liu, Y.P.f | Lin, A.g | Patroi, E.h | Shull, R.i | Thomas, O.j | Hall, M.J.j
Affiliations: [a] INRIM, Torino, Italy | [b] Hannam University, Daejeon, Korea | [c] PTB, Braunschweig, Germany | [d] TU Wien, Austria | [e] IMEM-CNR, Parma, Italy | [f] China Jiliang University, Hangzhou, Zhejiang,
China | [g] NIM, Bejing, China | [h] INCDIE ICPE-CA, Bucharest, Romania | [i] NIST, Gaithersburg, MD, USA | [j] NPL, Teddington, UK | Institute of Electrodynamics, Microwave and Circuit
Engineering, University of Technology, Vienna, Austria
Correspondence:
[*]
Corresponding author: F. Fiorillo, INRIM, Torino, Italy. Tel.:
+39 0113 9198 36; Fax: +39 0113 9198 34; E-mail: f.fiorillo@inrim.it
Abstract: We present the results of an international comparison regarding the
magnetic properties of hard magnets, measured using the Vibrating Sample
Magnetometer. The comparison involved eight different international
laboratories, plus two laboratories using the SQUID magnetometer. It was
directed, in particular, at the determination of the hysteresis loop parameters
of hard ferrite and magnetic tape samples. It was carried out in the framework
of the activity of the IEC TC68 Working Group 2. The statistical analysis of
the obtained results was performed according to standard rules (e.g. ISO and
EURAMET guidelines). The standard deviation around the mean of the laboratories
best estimates is found to be s ∼ 1% in anisotropic ferrites for all the
measured quantities: coercive fields H_{cJ} and
H_{cB}, high-field polarization J_{800
k}, polarization at remanence J_r, maximum energy
product (BH)_{max}. Isotropic ferrites show larger
dispersion of the best estimates of J_r and
H_{cB} (∼ 3%) and (BH)_{max}
(∼6%). For the quantities measured in the magnetic tapes (magnetic moment
under applied field H=400 kA/m m_{400 k} and at remanence
m_r, squareness S = m_{400 k}/m_r,
H_{cJ}) s is found to fluctuate around 2%. In all cases, the
relative expanded uncertainty of the reference value (weighted mean),
associated with a 95% confidence level, is at most ± 1.5%.
Keywords: Magnetic measurements, Vibrating Sample Magnetometer, hard magnets, measuring uncertainty
DOI: 10.3233/JAE-141786
Journal: International Journal of Applied Electromagnetics and
Mechanics, vol. 44, no. 3-4, pp. 245-252, 2014
