First order transitions in ACo₂compounds

Low-field memory and negative magnetization in semiconductors and polymers

“…is the dimensionless parameter of the Weiss molecular field model 14,15 . Now we employ the general Landau presentation,…”

“…where we used (13) and (m 1 − m 2 ) ∝ M from (15). The bulk component M = M (T, h) obeys (16) and depends on the sample magnetic history.…”

“…In general there is as much physical phenomena at room temperatures in applications of GL type equations, like (5), (15), or their extensions, to semi-, ultra-, and normal conductors with magnetic coupling of electrons as in applications of the original GL equation to superconductors with paired electrons at low temperatures. The Earth's field limit 0.5 Oe is especially unique for applications of semiconductors with negative spontaneous magnetization and magnetic memory states.…”

ANOMALOUS THERMAL VARIATION OF THE COBALT ANISOTROPY AND LONGITUDINAL SPIN FLUCTUATIONS IN Y2Co7

“…When this substitution occurs for every three, two or one YCo5 unit cell, the Y2Co7, YCo3 and YCo2 phases are generated respectively [I]. Whereas the magnetism of the cobalt in YCo6 keeps its character of well-established ferromagnetism, with magnetization and Curie temperature of the same order as in pure cobalt 121, an exchange enhanced Pauli paramagnetism is observed in YCo2 121, which undergoes a collective electron metarnagnetism in high fields [3]. This collapse is to be associated with a corresponding change in the cobalt atoms coordination in yttrium.…”

Experimental Study of the Magnetocaloric Effect in the Pseudo Binary Laves-Phase Compounds

“…The Co-atom moments in the light rare-earth compounds range from 0.5 to 0.8 µ B , while the moments are almost unchanged (˜1.0 µ B ) for the compounds with the heavy rare-earth elements. The induced moments are aligned in parallel to the 4f moments in the light rare-earth compounds and are antiparallel in the heavy rare-earth compounds [8]. DyCo 2 , HoCo 2 and ErCo 2 were selected from a great number of intermetallic compounds; their Curie temperatures are 140, 76 and 35 K, respectively [9].…”