Field step size and temperature effects on the character of the magnetostructural transformation in a Gd5Ge4 single crystal

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2007-10-10
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Gschneidner, Karl
Schlagel, Deborah
Lograsso, Thomas
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Ames National Laboratory
Abstract

The critical magnetic fields required to induce the magnetostructural transformation below ∼30 K in Gd5Ge4 are dependent on the size of the magnetic-field step employed during isothermal measurements of magnetization: the smaller the step, the lower the critical field. The influence of the magnetic-field step size on the character of the magnetostructural transition in Gd5Ge4 diminishes as temperature increases, nearly disappearing above ∼30 K. Decreasing the size of the field step also leads to the formation of multiple steps in the magnetization. The steps are reproducible in the same sample at low temperatures (below ∼9 K) but they become stochastic and irreproducible at high temperatures (above ∼20 K). The varying dynamics of both the magnetization and demagnetization processes is associated with approaching true equilibrium states and, therefore, reduction of the size of the magnetic-field step at low temperatures plays a role similar to the dominant role of thermal fluctuations at high temperatures. Similar phenomena are expected to occur in other martensiticlike systems, e.g., the manganites.

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This article is from Physical Review B 76, no. 13 (2007): 134406, doi:10.1103/PhysRevB.76.134406.

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Mon Jan 01 00:00:00 UTC 2007
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