Quantum phase transition and ferromagnetism in Co_1+xSn

Authors

Rabindra Pahari, University of Nebraska - LincolnFollow
Balamurugan Balasubramanian, University of Nebraska-LincolnFollow
Rohit Pathak, Indian Institute of Technology Mandi
Manh Coung Nguyen, The Ames Laboratory
Shah R. Valloppilly, University of Nebraska - LincolnFollow
Ralph Skomski, University of Nebraska - LincolnFollow
Arti Kashyap, Indian Institute of Technology MandiFollow
Cai-Zhuang Wang, The Ames LaboratoryFollow
Kai-Ming Ho, The Ames LaboratoryFollow
George C. Hadjipanayis, University of DelawareFollow
David J. Sellmyer, University of Nebraska - LincolnFollow

Date of this Version

2019

Citation

PHYSICAL REVIEW B 99, 184438 (2019)

DOI: 10.1103/PhysRevB.99.184438

Comments

©2019 American Physical Society. Used by permission.

Abstract

The onset of ferromagnetism in cobalt-tin alloys is investigated experimentally and theoretically. The Co₁₊xSn alloys were prepared by rapid quenching from the melt and form a modified hexagonal NiAs-type crystal structure for 0.45 ≤ x ≤ 1. The magnetic behavior is described analytically and by density-functional theory using supercells and the coherent-potential approximation. The excess of Co concentration x, which enters the interstitial 2d sites in the hypothetical NiAs-ordered parent alloy CoSn, yields a Griffiths-like phase and, above a quantum critical point (x_c ≈ 0.65), a quantum phase transition to ferromagnetic order. Quantum critical exponents are determined on the paramagnetic and ferromagnetic sides of the transition and related to the nature of the magnetism in itinerant systems with different types of chemical disorder.