Spin–singlet competition responsible for magnetization plateau associated with magnetocaloric effect in a tetrameric chain

L.J. Ding, Y. Zhong, S.W. Fan, X.P. Huang and L.Y. Zhu

Physica A: Statistical Mechanics and its Applications, 2015, vol. 423, issue C, 1-10

Abstract: The quantum phase transitions (QPTs) and magnetization plateau properties, together with magnetocaloric effect (MCE) of the tetrameric chain are investigated by means of Green’s function theory. We reveal the uniform, dimeric and gapped (gapless) tetrameric phases, which are explicitly confirmed by the field dependence of magnetization. The spin–singlet competition is proposed to make clear the magnetization plateaus and QPTs. Simultaneously, the QPTs and quantum critical points are identified by the dips of the isoentropes, or equivalently the sharp maxima of entropy at ultra-low temperature, as well as the local minima of specific heat and the valley–peak structure of magnetic cooling rate with its sign changed. In addition, the temperature (T) and magnetic field (h) dependence of magnetic entropy change (ΔS) exhibits prominent inverse magnetocaloric effect (IMCE), implying adiabatic magnetization can generate cooling, which follows a power law dependence of h: ΔS∼hn. The local exponent n≈2 is independent of h and T at low fields, which was observed in the antiferromagnetic materials experimentally. It is also found that the stronger the dimerization is, the larger the IMCE is, which would provide a clue to design antiferromagnetic refrigerant materials for use in magnetic cooling devices with low field controlling.

Keywords: Quantum phase transition; Magnetization plateau; Magnetocaloric effect; Tetrameric chain; Spin-singlet competition; Quantum critical points (search for similar items in EconPapers)
Date: 2015
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378437114010619
Full text for ScienceDirect subscribers only. Journal offers the option of making the article available online on Science direct for a fee of $3,000

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:phsmap:v:423:y:2015:i:c:p:1-10

DOI: 10.1016/j.physa.2014.12.026

Access Statistics for this article

Physica A: Statistical Mechanics and its Applications is currently edited by K. A. Dawson, J. O. Indekeu, H.E. Stanley and C. Tsallis

More articles in Physica A: Statistical Mechanics and its Applications from Elsevier
Bibliographic data for series maintained by Catherine Liu ().