Посилання:Direct evidence of the low-temperature cluster-glass magnetic state of Nd²/₃Ca¹/₃MnO₃ perovskite / A. Feher, V. Desnenko, E. Fertman, S. Dolya, M. Kajňaková, A. Beznosov // Физика низких температур. — 2012. — Т. 38, № 7. — С. 828-832 . — Бібліогр.: 19 назв. — англ.
Підтримка:This paper is dedicated to Professor Viktor Valentinovich
Eremenko on the occasion of his 80th birthday. One
of authors (A.F.) is very thankful to Prof. Eremenko for
decades of fruitful collaboration. Viktor Valentinovich was
and still is an excellent mentor in the field of magnetism
for the whole Košice Low Temperature Group.
Authors are thankful to Dr. D. Sheptyakov (PSI, Switzerland)
and to Dr. D. Khalyavin (ISIS, United Kingdom)
for fruitful collaboration.
This work was supported by the SAS Centre of Excellence
CFNT MVEP, by the ERDF EU (European Union
European regional development fund) grant under the contract
No. TMS26220120005 and by the Slovak Grant Agency
VEGA-1/0159/09. The financial support of U.S. Steel Košice
is gratefully acknowledged.
In the presented study we have revealed a giant exchange bias in a colossal magnetoresistance
Nd²/₃Ca¹/₃MnO₃ perovskite at low temperatures, evident of an intrinsic exchange coupling in this compound.
The phenomena found confirms our previous assumption that the low-temperature magnetic structure of the
compound is represented by small (nanosized) ferromagnetic clusters immersed within the charge-ordered antiferromagnetic
matrix. Magnetic behavior of the Nd²/₃Ca¹/₃MnO₃ perovskite is consistent with a cluster-glass
magnetic state and does not agree with a classical spin-glass state observed in a variety of disordered magnetic
systems. We think that the cluster-glass magnetic behavior of Nd²/₃Ca¹/₃MnO₃ originates from the selforganized
phase-separated state of the compound. The Cole-Cole analysis of the dynamic susceptibility at lowtemperatures
has shown extremely broad distribution of relaxation times, indicating that spins are frozen at
a “macroscopic” time scale. Slow relaxation of the zero-field-cooled magnetization has been experimentally revealed
as well. This slow relaxation confirms the cluster-glass magnetic state of the compound. Two strongly
different relaxation mechanisms were found: the first one is characteristic for temperatures below the freezing
temperature Tg ∼ 60 K, the second one is characteristic for higher temperatures.