Lab Home | Phone | Search
Center for Nonlinear Studies  Center for Nonlinear Studies
 Home 
 People 
 Current 
 Executive Committee 
 Postdocs 
 Visitors 
 Students 
 Research 
 Publications 
 Conferences 
 Workshops 
 Sponsorship 
 Talks 
 Seminars 
 Postdoc Seminars Archive 
 Quantum Lunch 
 Quantum Lunch Archive 
 P/T Colloquia 
 Archive 
 Ulam Scholar 
 
 Postdoc Nominations 
 Student Requests 
 Student Program 
 Visitor Requests 
 Description 
 Past Visitors 
 Services 
 General 
 
 History of CNLS 
 
 Maps, Directions 
 CNLS Office 
 T-Division 
 LANL 
 
Thursday, May 17, 2012
2:00 PM - 3:00 PM
CNLS Conference Room (TA-3, Bldg 1690)

Postdoc Seminar

Formation of magnetic microphases in Ca3Co2O6

Yoshitomo Kamiya
T-4 and CNLS

We study a frustrated quantum Ising model relevant for Ca3Co2O6 that comprises a triangular lattice of weakly coupled ferromagnetic chains. Our quantum Monte Carlo simulation shows that the chains become ferromagnetic and form a three-sublattice “up-up-down” structure in the lowest-T regime below T=T_{CI}. In contrast, long-period spin-density-wave (SDW) modulations along the chains are stabilized for T_{CI} < T < Tc in agreement with recent experiments by Agrestini et al [1]. We also discuss a simple mean-field theory revealing quasi-continuous change of the modulation periodicity as a function of T, implying the existence of metastable states in the SDW phase, which explains the slow low-temperature dynamics that has been observed in Ca3Co2O6 [2]. Closely related multiferroic material Ca3MnCoO6 [3] will also be discussed. References: [1] S. Agrestini et al., Phys. Rev. Lett., 101, 097207 (2008) [2] T. Moyoshi and K. Motoya, J. Phys. Soc. Jpn., 80, 034701 (2011) [3] Y. J. Jo et al., Phys. Rev. B. 79, 012407 (2009)

Host: Kipton Barros, T-4 and CNLS