Magnetic phase diagram of the frustratedS=12chain magnet LiCu2O2

Abstract

We present the results of the magnetization and dielectric constant measurements on untwinned single crystal samples of the frustrated S = 1/2 chain cuprate LiCu2O2. Novel magnetic phase transitions were observed. A spin flop transition of the spiral spin plane was observed for the field orientations H a, b. The second magnetic transition was observed at H ≈ 15 T for all three principal field directions. This high field magnetic phase is discussed as a collinear spin-modulated phase which is expected for an S=1/2 nearest-neighbor ferromagnetic and next-nearest-neighbor antiferromagnetic chain system.

Thermodynamic properties of LiCu2O2 multiferroic compound

“…It can be seen that our simulation result is qualitatively in good agreement with experimental data in two aspects. First, m (χ m ) for h c exceeds that for h a, b, reproducing the anisotropic behaviors observed in LiCu 2 O 2 [8,10]. Moreover, the negligible differences in the magnetization data between a and b axis are also in accord with recent report on untwinned crystals [13].…”

“…Actually, a class of low-dimensional cuprate oxides such as LiCuVO 4 , Li 2 CuO 2 , Li 2 ZrCuO 4 etc. were reported to have such spiral magnetic orders [4][5][6][7][8][9]. And it is believed that the research on the ferroelectricity of magnetic origin in these low-dimensional compounds will be helpful in understanding the multiferroic nature [10,11].…”

Anisotropic exchange in LiCu2O2

“…it turned out to be a paramount example of a multiferroic due to the correlation between spin helicity and electric polarization. [31][32][33] Detailed investigations to resolve the phase diagram of LiCu 2 O 2 have been performed by means of magnetization and dielectric measurements 34 as well as neutron scattering, 19 electron spin resonance (ESR), and nuclear magnetic resonance (NMR) studies. 35 Basically, a susceptibility maximum at a temperature T max = 38 K typical for a low-dimensional antiferromagnet and two subsequent phase transitions at T N1 = 24.5 K and T N2 = 23 K into the spin-spiral structure, where the latter is accompanied by the occurrence of ferroelectricity, characterize the magnetic and electric properties of LiCu 2 O 2 at low magnetic fields.…”

Temperature evolution of structural and magnetic properties of stoichiometric LiCu2O2: Correlation of thermal expansion coefficient and magnetic order

“…The exact nature and origin of this magnetic structure (e.g. propagation direction and planes) is still under debate [2][3][4][5][6][7][8][9][10][11][12]. The crystal structure of LiCu 2 O 2 has orthorhombic symmetry (space group Pnma with a = 5.730(1), b = 2.8606(4), c = 12.417(2) Å) and represents an alternation of three layers along the c axis: (i) -Cu + (1)-, (ii) -O(1)Cu 2+ (2)O(2)Li-, and (iii) -LiO(2)Cu 2+ (2)O(1)- [13].…”