Eur. Phys. J. E (2017) 40: 96
https://doi.org/10.1140/epje/i2017-11584-6

Regular Article

Random field Ising model in a uniform magnetic field: Ground states, pinned clusters and scaling laws

¹ School of Physical Sciences, Jawaharlal Nehru University, 110067, New Delhi, India
² Department of Physics, Indian Institute of Technology, 110016, Hauz Khas, New Delhi, India

^* e-mail: purijnu@gmail.com

Received: 7 July 2017
Accepted: 23 October 2017
Published online: 8 November 2017

Abstract

In this paper, we study the random field Ising model (RFIM) in an external magnetic field h . A computationally efficient graph-cut method is used to study ground state (GS) morphologies in this system for three different disorder types: Gaussian, uniform and bimodal. We obtain the critical properties of this system and find that they are independent of the disorder type. We also study GS morphologies via pinned-cluster distributions, which are scale-free at criticality. The spin-spin correlation functions (and structure factors) are characterized by a roughness exponent . The corresponding scaling function is universal for all disorder types and independent of h.