Abstract:

The metastable property of glasslike dynamics at low temperature of Gd₅Ge₄ was presented in contrast to the stable frozen spin glass state in cobaltite La_0.88Sr_0.12CoO₃(LSCO). Through investigating the effect of temperature cycle on magnetization at the low temperature region after the zero field cooled procedure ofGd₅Ge₄andLa_0.88Sr_0.12CoO₃respectively, it was found that the magnetization continues to increase with increasing the temperature cycle in Gd₅Ge₄, while there was hardly any effect on magnetization inLa_0.88Sr_0.12CoO₃. The dc magnetization and ac susceptibility were also measured on Gd₅Ge₄ and La_0.88Sr_0.12CoO₃. The peaks of ac susceptibility in Gd₅Ge₄ did not move to the higher temperature region with increasing frequency, which were different from the phenomena of La_0.88Sr_0.12CoO₃. This kind of magnetic glass state in Gd₅Ge₄ is quite different from conventional spin glass.

Key words: magnetic glass sate, spin glass, magnetocaloric material