Enhancement of magnetocaloric effect in CoMn0.9Fe0.1Ge alloy

• Published in: Journal of alloys and compounds Vol. 641; pp. 69 - 73
• Main Authors: Yüzüak, E., Dincer, I., Elerman, Y., Dumkow, I., Heger, B., Yuce Emre, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.08.2015
• Subjects: CoMnGe alloy; Magnetocaloric effect; Martensitic phase transition; Magnetocaloric effect; Martensitic phase transition; CoMnGe alloy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2015.04.062

•The structural and magnetic phase transitions of CoMn0.9Fe0.1Ge are investigated.•The entropy change value is −34.9Jkg−1K−1 for magnetization under CoMn0.9Fe0.1GeH=5T.•The entropy change value is −33.6Jkg−1K−1 for demagnetization under ΔH=5T.•The adiabatic temperature change value of CoMn0.9Fe0.1Ge is estimated from heat capacity measurements 8.5K under ΔH=2T. The magnetic and magnetocaloric properties of CoMn0.9Fe0.1Ge alloy has been investigated by using of electron microscopy, X-ray diffraction, calorimetric, heat capacity and magnetic measurements. The substitution of Fe atoms for Mn atoms in the CoMnGe system leads to a decrease in the martensitic transition temperature from 650K to room temperature (RT) and presents the magnetostructural properties in vicinity of RT. In order to assess MCE, temperature dependent of magnetization measurements have performed under applying variable magnetic fields. The largest entropy change values are −34.9Jkg−1K−1 (magnetization) and −33.6Jkg−1K−1 (demagnetization) for ΔH=5T. The adiabatic temperature change value of CoMn0.9Fe0.1Ge is calculated 8.5K for 2T from magnetic and heat capacity measurements. The density of states of electrons at Fermi level and the Debye temperature values of this alloy are found 1.19 states eV−1atom−1 and 353K from low temperature heat capacity measurements. This giant magnetocaloric effect makes this material a very promising candidate for future RT cooling applications.