Experimental and Theoretical Investigations of Fe-Doped Hexagonal MnNiGe

S Shanmukharao Samatham; Akhilesh Kumar Patel; Ashish Kumar Mishra; Alexey V Lukoyanov; Lyubov N Gramateeva; Archana Lakhani; Ganesan Vedachalaiyer; Suresh Krishnawarrier Gopinatha Warrier

doi:10.1021/acsomega.2c01571

Experimental and Theoretical Investigations of Fe-Doped Hexagonal MnNiGe

ACS Omega. 2022 May 17;7(21):18110-18121. doi: 10.1021/acsomega.2c01571. eCollection 2022 May 31.

Authors

S Shanmukharao Samatham¹, Akhilesh Kumar Patel², Ashish Kumar Mishra³, Alexey V Lukoyanov^{4

5}, Lyubov N Gramateeva⁴, Archana Lakhani³, Ganesan Vedachalaiyer^{6

3}, Suresh Krishnawarrier Gopinatha Warrier²

Affiliations

¹ Department of Physics, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabad 500075, India.
² Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.
³ UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001, Madhya Pradesh, India.
⁴ M. N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia.
⁵ Ural Federal University, 620002 Ekaterinburg, Russia.
⁶ Medi-Caps University, A.B. Road, Pigdamber, Rau, Indore 453331, Madhya Pradesh, India.

Abstract

We report a comprehensive investigation of MnNi_0.7Fe_0.3Ge Heusler alloy to explore its magnetic, caloric, and electrical transport properties. The alloy undergoes a ferromagnetic transition across T _C ∼ 212 K and a weak-antiferromagnetic transition across T _t ∼ 180 K followed by a spin-glass transition below T _f ∼ 51.85 K. A second-order phase transition across T _C with mixed short and long-range magnetic interactions is confirmed through the critical exponent study and universal scaling of magnetic entropy and magnetoresistance. A weak first-order phase transition is evident across T _t from magnetization and specific heat data. The frequency dependent cusp in χ_AC(T) along with the absence of a clear magnetic transition in specific heat C(T) and resistivity ρ(T) establish the spin glass behavior below T _f. Mixed ferromagnetic and antiferromagnetic interactions with dominant ferromagnetic coupling, as revealed by density functional calculations, are experimentally evident from the large positive Weiss temperature, magnetic saturation, and negative magnetic-entropy and magnetoresistance.