Magnetism of A2Cu2Mo3O12 (A=Rb or Cs): Model compounds of a one-dimensional spin-1∕2 Heisenberg system with ferromagnetic first-nearest-neighbor and antiferromagnetic second-nearest-neighbor interactions

Abstract

Magnetic susceptibility and magnetization showed that A2Cu2Mo3O12 (A=Rb or Cs) includes a one-dimensional spin-1∕2 Heisenberg system with ferromagnetic first-nearest-neighbor (1NN) and antiferromagnetic second-nearest-neighbor (2NN) competing exchange interactions (competing system). Values of the 1NN and 2NN interactions are estimated as J1=−138K and J2=51K for A=Rb or J1=−93K and J2=33K for A=Cs. Rb2Cu2Mo3O12 is a suitable compound to study the competing system with ferromagnetic J1, because other interactions are small. The value of J2∕J1 indicates that Rb2Cu2Mo3O12 has a spin-singlet incommensurate ground state.

Rb-NMR study of the quasi-one-dimensional competing spin-chain compound Rb2Cu2Mo3Matsui1, Yagi2, Hoshino3 et al. 2017Phys. Rev. BSelf Cite164150View full textAdd to dashboardCite

“…The present system contains the three Rb sites 4e, 4d and 8f in the unit cell, and the distance between each of these sites and its nearest Cu site is nearly alike distributing between 4.01 and 5.57 Å [1,2]. In the powder spectrum of NMR, these three sites forms a single peak for the central transition between = ±½, combining all of the Knight shift anisotropy, its site difference, and eqq-broadening.…”

“…The title compound Rb 2 Cu 2 Mo 3 O 12 , the quasi-one dimensional quantum spin chain system, involves both of these two phenomena [1][2][3]. It consists of so-called ribbon-chains of = ½ spins, in which the ferromagnetic and antiferromagnetic exchange interactions work on the nearest neighboring and the next nearest neighboring spins, respectively.…”

Ground State of Quasi-One Dimensional Competing Spin Chain Cs2Cu2Mo3O12 at zero and Finite Fields

“…Field-dependence of T N and magnetization curve [1,2,13]. T N vanishes above 6 T, which is approximately 2/3 of the saturation field.…”

“…The powder sample was synthesized by a conventional solid solution method [1,2]. Zero (ZF) and longitudinal (LF) field-SR measurements [15,16] were performed at Riken-RAL Muon facility using a spin-polarized pulsed surface-muon ( + ) beam with a momentum of 27 MeV/c.…”

“…The ground state of the competing-spin chain R 2 Cu 2 Mo 3 O 12 [1,2] has attracted much interest, not only for the possibility of spin nematic state [3][4][5][6][7][8][9][10][11], but because the two isomorphic compounds with R= Cs and Rb show different ground states [11][12][13][14]. While the former shows a magnetic order at T N = 1.8 K, the latter shows a small spin gap of /k B = 1.6K.…”