Magnetocaloric Effect with Very Small Magnetic Hysteresis Losses of CoMn1-xTixGe Alloys


YILDIRIM O., Tozkoparan O., Yuzuak E. , Elerman Y., Dincer I.

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ss.5733-5737, 2017 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: Konu: 11
  • Basım Tarihi: 2017
  • Doi Numarası: 10.1007/s11661-017-4282-8
  • Dergi Adı: METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
  • Sayfa Sayıları: ss.5733-5737

Özet

The effects of Ti substitution for Mn and heat treatment on structural, magnetic, and magnetocaloric properties of CoMnGe alloy have been investigated using electron microscopy, X-ray diffraction, calorimetric, and magnetic measurements. According to X-ray diffraction measurements, CoMn1-xTixGe alloys are in a single phase hexagonal structure at room temperature. It is found that the as-cast CoMn0.95Ti0.05Ge alloy shows a magnetostructural phase transition close to room temperature. The transition shows a large magnetic entropy change and a small hysteresis in the isothermal magnetic field-dependent magnetization measurements. After annealing, the phase transition temperature decreases slightly and the magnetization is sharply decreasing at Curie temperature. The sharp change of magnetization at phase transition temperature is accompanied by a significant increase in the magnetic entropy change, i.e., magnetic entropy change value for the magnetic field change of 1 T was increased from -3.3 to -6.3 J kg(-1) K-1. Moreover, after annealing, hysteresis losses reduced significantly for Delta H = 7 T. Accordingly, the heat treatment has a significant effect on magnetocaloric properties of the CoMn0.95Ti0.05Ge alloy.