Revealing magnetic and physical properties of TbFe4.4Al7.6: experiment and theory

S Shanmukharao Samatham; Saurabh Singh; S Shravan Kumar Reddy; Santhosh Kumar A; Sankararao Yadam; P D Babu; Tsunehiro Takeuchi; K G Suresh

doi:10.1088/1361-648X/ad2719

Revealing magnetic and physical properties of TbFe_4.4Al_7.6: experiment and theory

J Phys Condens Matter. 2024 Feb 20;36(20). doi: 10.1088/1361-648X/ad2719.

Authors

S Shanmukharao Samatham¹, Saurabh Singh^{2

3}, S Shravan Kumar Reddy¹, Santhosh Kumar A¹, Sankararao Yadam⁴, P D Babu⁵, Tsunehiro Takeuchi³, K G Suresh⁶

Affiliations

¹ Department of Physics, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabad 500 075, India.
² Penn State University, University Park, PA 16802, United States of America.
³ Energy Materials Laboratory, Toyota Technological Institute, Hisakata Tempaku, Nagoya 468-8511, Japan.
⁴ Department of Physics, CVR College of Engineering, Ibrahimpatnam, Ranga Reddy, Telangana 501 510, India.
⁵ UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC Campus, Mumbai 400 085, India.
⁶ Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.

PMID: 38328924
DOI: 10.1088/1361-648X/ad2719

Abstract

We report on the magnetic, electrical transport, caloric and electronic structure properties of TbFe_4.4Al_7.6polycrystalline alloy using experiment and theory. The alloy crystallizes in tetragonal structure with I4/mmm space group with lattice parametersa = b= 8.7234(5) Å andc= 5.0387(6) Å. It is ferrimagnetic with a compensation temperature ofTcmp∼151 K, Curie-Weiss temperatureθCW∼172.11 K and an effective magnetic momentμeff= (2.37±0.07)μB/f.u withZ= 2. At low temperatures, kinetic arrest-like first-order phase transition is realized through the thermal hysteresis between field-cooled cooling and field-cooled warming curves ofM(T) and virgin curves ofM(H) andρ(H)which are outside the hysteresis loops with metamagnetic transition. The high magnetic field suppression of multiple transitions and reduced coercive fieldHcoerand remnant magnetizationMremwith increasing temperature are reported.HcoerandMremcease to exist above the compensation temperatureTcmp. A correlation between the isothermal magnetization and resistivity is discussed. Specific heatC(T) analysis reveals a Sommerfeld parameter ofγ= 0.098 J⋅mol-1⋅K-2and a Debye temperature ofθD∼351.2 K. The sample is metallic as inferred from theρ(T)behavior and Sommerfeld parameter. The magnetoresistance of the alloy is low and negative which indicates the suppression of weak spin-fluctuations. This alloy avoids the tricritical point despite first-to-second order phase transition. The electronic and magnetic structure calculations, by making use of full potential linearized augmented plane wave method, suggest metallic ferrimagnetic ground state of TbFe_4.4Al_7.6with Tb atoms contributing ferromagnetically (5.87μB) and Fe atoms with antiferromagnetic contribution (2.67μB), in close agreement with the experimental observation.

Keywords: ferrimagnetism; first order phase transition; first principle calculations; kinetic arrest; magnetoresistance.