A long-range model with energy–spin coupling and critical properties of hexagonal antiferromagnetic manganites. (15th February 2018)

• Record Type: Journal Article
• Authors: Singh, Rohit; Nandy, Malay K
• Is Part Of: Journal of statistical mechanics. (2018:Feb.)
• Publication Date: 2018-02-15
• Subjects: 3; Statistical mechanics -- Periodicals; Mechanics -- Statistical methods -- Periodicals; 530.1305
• DOI: 10.1088/1742-5468/aaa8ed
• Languages: English
• ISSNs: 1742-5468

Abstract

Abstract: We investigate the critical properties of a model Hamiltonian involving a four-spin term with long-range interaction together with energy–spin coupling. Employing Wilson's momentum-shell decimation scheme at one-loop order, we perform a renormalization-group analysis and obtain the critical exponents corresponding to the non-trivial fixed point. We find that the specific heat exponent α lies in the negative range − 0.20 < α < 0 in the allowed range of a parameter ρ ocurring in the four-spin long-range coupling. This predicted theoretical range is consistent with the range − 0.19 ⩽ α ⩽ − 0.09 observed in the thermal measurements of Oleaga et al (2012 Phys. Rev . B85 184425) in the vicinity of the Néel temperatures of various experimental samples of hexagonal antiferromagnetic manganites.