Thermal Properties of (DyxGd1-x)3Ga5O12 Garnet Single Crystals
The solid solution (DyxGd1-x)3Ga5O12 garnet is proposed as a high heat capacity material below 2 K for regenerator. A short range order interaction resulting from the magnetic frustration in Gd3Ga5O12 gives a considerably high heat capacity below 2 K. At a magnetic field B = ~1 T, Gd3Ga5O12 has a sharp anomaly in its specific heat at ~0.37 K related to an antiferromagnetic transition, keeping the large heat capacity. By substituting Gd ion by Dy ion, an anisotropy will be produced in (DyxGd1-x)3Ga5O12 and it enhances the antiferromagnetic long range order interactions. The specific heat measurement for (Dy0.5Gd0.5)3Ga5O12 at B = 0 T showed that heat capacity of (Dy0.5Gd0.5)3Ga5O12 is comparable largely to that of Gd3Ga5O12 and a transition temperature may be found below 0.6 K. From the thermal conductivity measurement, a strong correlation with magnetic field has been found. The reduction in the thermal conductivity caused by the magnetic field is the largest in Dy3Ga5O12 and it decreases by increasing the concentration of Gd ion.
KeywordsPhonon Scattering Magnetic Field Dependence Magnetocaloric Effect Thermal Conductivity Measurement Magnetic Refrigerant
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