Visual evidence of the magnetic glass state and its re-crystallization in Gd5Ge4M. K. Chattopadhyay1, S. B. Roy1, K. Morrison2, J. D. Moore2, G. K. Perkins2, L. F. Cohen2, K. A. Gschneidner jr.3 and V. K. Pecharsky3
1 Magnetic and Superconducting Materials Section, Raja Ramanna Centre for Advanced Technology Indore 452 013, India
2 Blackett Laboratory, Imperial College of Science Technology and Medicine - London SW7 2BZ, UK, EU
3 Ames Laboratory of the US DOE and Department of Materials Science and Engineering, Iowa State University Ames, IA 50011-3020, USA
received 3 December 2007; accepted in final form 24 July 2008; published September 2008
published online 3 September 2008
We present the results of scanning Hall probe microscopy experiments on polycrystalline Gd5Ge4 providing visual evidence of the formation of a ”magnetic-glass” out of a kinetically arrested first-order antiferromagnetic-to-ferromagnetic transition. This magnetic-glass state consists of equilibrium ferromagnetic microscopic regions distributed randomly in a metastable antiferromagnetic matrix. In addition we show how the introduction of energy fluctuations in the system produces spatially dependent signs of growth of ferromagnetic phase or re-crystallization of this 'magnetic-glass'.
75.30.Kz - Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.).
64.70.P- - Glass transitions of specific systems.
75.10.Nr - Spin-glass and other random models.
© EPLA 2008