Spin Density Wave in Insulating Ferromagnetic Frustrated Chain LiCuVO₄

Abstract

We study field induced quantum phase in weakly-coupled ferromagnetic frustrated chain LiCuVO 4 by neutron diffraction technique. A new incommensurate magnetic peak is observed at H ≥ 8.5 T. The field dependent propagation vector is identified with the spin density wave correlation in the theoretically predicted magnetic quadrupole order. Quantum fluctuation, geometrical frustration, and interchain interaction induce the exotic spin density wave longrange order in the insulating magnet. KEYWORDS: ferromagnetic frustrated chain, nematic state, spin density waveOne of hot topics in condensed matter science is to search a spin liquid 1) that exhibits order not in conventional two spin correlation but in others such as magnetic multipole 2) or spin chirality. 3) 1D frustrated spin chain with ferromagnetic nearest neighbor interaction (J 1 ) and antiferromagnetic next nearest neighbor interaction (J 2 ) is a zoo of such novel states.While in case of the classical spin the spontaneous rotational symmetry breaking induces spiral long-range order (LRO) for |J 1 |/J 2 < 4, those of quantum spin does not exhibit the LRO because of Mermin-Wagner theorem. 4) Instead solely the spin chirality, κ = S i × S j does order with Z 2 symmetry broken and vector chiral (VC) phase appears. 5,6) Applying magnetic field makes the system more complex and interesting. At the field close to the ferromagnetic polarized phase, a pair of magnons form bound state 7) and its Bose condensation at around q = π induces quasi-LRO of the magnetic quadrupole. 8) The quadrupole phase is characterized by the following longitudinal spin and transverse nematic correlations, 9)The former exhibits magnitude modulation with the characteristic wave vector 2k F = 2πρ, where ρ is the density of bound two-magnon, ρ = 1/2(1/2− S z ). A z , A m , andà m are positive

Magnetic field driven 2D-3D crossover in theS=12frustrated chain magnetLiCuVO4

“…This relation has been traced experimentally in the field range below 15 T (Refs. [16,25]), and therefore, the value k ic is significantly less than π/b at all fields above H c2 . The elongation of the spin-modulation period along the chain in the field leads to a random shift of its phase at each defect [see Fig.…”

Frustrated Zig-Zag Spin Chains Formed by Hydrogen Bonds in~[Cu(H2O)(OH)(tmen)]2[Pd(CN)4]·2H2O

“…Consequently, the presence of additional exchange paths through the HBs leads to the creation of complex motifs with alternating or frustrating exchange interactions. Among the different magnetic systems, frustrated spin chains can display interesting properties such as the appearance of spontaneous dimerization, chiral order, and the presence of field-induced spin-density waves depending on the ratio between frustrating and interchain exchange interaction [1][2][3]. Here we report thermodynamic and magnetic properties of a novel dimeric Fig.…”

NaCuMoO4(OH) as a Candidate Frustrated J1–J2 Chain Quantum Magnet

“…Among these compounds, the most often studied is LiCuVO 4 with J 1 = −19 K and J 2 = 44 K [25]. It has been shown using large single crystals that LiCuVO 4 exhibits an incommensurate helical order at low fields [25][26][27][28][29], which may be a 3D analogue of the vector chirality …”

“…Among these compounds, the most often studied is LiCuVO 4 with J 1 = −19 K and J 2 = 44 K [25]. It has been shown using large single crystals that LiCuVO 4 exhibits an incommensurate helical order at low fields [25][26][27][28][29], which may be a 3D analogue of the vector chirality order in the J 1 -J 2 chain, and a longitudinal SDW order at intermediate fields [26][27][28][29]. Furthermore, a spin nematic phase, a 3D analogue of the spin nematic state, has been suggested slightly below the saturation field of 44.4 T at H c, where the magnetization shows a linear field dependence [30].…”

“…One more important requirement for a good candidate compound is the availability of a large and clean single crystal. Among the compounds shown in Table I [20][21][22], and LiCuVO 4 [23][24][25][26][27][28][29][30][31]. However, "a cleanness" of these crystals seems unsatisfactory: a natural crystal of PbCuSO 4 (OH) 2 is contaminated by impurities, and the two Li-containing crystals seem to suffer from Li deficiency or an interchange between Li and Cu atoms [24].…”