Spin-glass-like behaviour and low-temperature specific heat of amorphous ErxNi100-xrandom magnetic anisotropy system
Year: 1995
Type: article
Abstract: Spin-glass-like behaviour and low-temperature specific heat have been investigated for bulk amorphous Er x N 100-x , (x=33, 50 and 80) alloys prepared by high-rate direct-current sputtering. The competition between ferromagnetic and antiferromagnetic interactions arising from the exchange fluctuations is negligibly small in this system, in contrast to that in amorphous Er-Cu alloys. The random magnetic anisotropy (RMA) suppresses the ferromagnetic coupling, resulting in a spin-glass-like state. The magnetization per Er atom becomes smaller with increasing Er content owing to the increase in the RMA. At the spin freezing temperature T f the low-temperature specific heat exhibits a broad maximum, which becomes narrower with the decrease in Er content. It should be noted that the temperature at which the magnetic specific heat of the amorphous Er 33 Ni 67 alloy reaches a maximum value coincides with the T f determined by the alternating-current magnetic susceptibility measurement. The splitting of the ground state from J=15/2 into a Kramers doublet is caused by the electrostatic field, being accompanied by a Schottky-type specific heat with a linear temperature dependence. The magnetic entropy at T f is estimated to be about 45-60% of the theoretical value, being much larger than those for crystalline dilute spin-glass systems. Moreover, the plot of the magnetic specific heat versus T 3/2 is linear at low temperatures. Therefore, it is considered that a ferromagnetic-like spin wave is excited, although its magnetic structure is not ferromagnetic.
Authors: Y Hattori, K Fukamichi, K Suzuki, H Aruga-Katori, T Goto
Institution: Tohoku University
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2014362475