Magnetization and Spin Correlation of Two-Dimensional Triangular Antiferromagnet LuFe₂O₄

Electronic states ofRFe2O4(R=Lu,Yb,TmLafuerza1, García2, Subı́as3 et al. 2014Phys. Rev. B10241View full textAdd to dashboardCite

“…Magnetic measurements were carried out between 5 and 300 K using a commercial Quantum Design superconducting quantum interference device (SQUID) magnetometer. Figure 1 shows the temperature dependence of the zero-field-cooled (ZFC) and field-cooled (FC) magnetization for various RFe 2 O 4 samples (R = Lu, Yb, Tm) and applied magnetic field (H) of either 4 T or 5 T. The ZFC-FC magnetic irreversibility at low temperatures and the strong anisotropy with an easy magnetic direction parallel to the crystallographic c axis agree with previous reports in the literature [13][14][15][16]. We would like to emphasize that magnetization reversal can only be achieved, for a given H, at temperatures where the ZFC-FC curves overlap.…”

“…On the other hand, the YFe 2 O 4 compound shows a complex low temperature structure with various crystal distortions coupled * E-mail: sara.lafuerza@esrf.fr to two successive Verwey-type metal-insulator transitions at about 240 and 190 K [11,12] not observed in the Lu, Yb, and Tm compounds. Concerning the magnetic properties, LuFe 2 O 4 [13,14], YbFe 2 O 4 [15], and TmFe 2 O 4 [16] exhibit ferrimagnetic ordering below T N ≈ 240−250 K, whereas the YFe 2 O 4 compound is antiferromagnetic [11].…”

Intrinsic electrical properties of LuFe2O4

“…The strong magnetic anisotropy with an easy magnetic axis parallel to the c axis, the ZFC-FC magnetic irreversibility in both geometries, and the sharp magnetic transition below 240 K are in accordance with previous reports in the literature. 11,[27][28][29] Electrical dc resistivity measurements were made on sintered polycrystalline bar-shaped samples (ρ pol ) with a size of 1 × 2 × 6 mm 3 and on single-crystal bar-shaped samples of a size of 0.5 × 0.6 × 1 mm 3 and 0.5 × 1 × 4 mm 3 with the electric field parallel (ρ c ) and perpendicular (ρ ab ) to the hexagonal c axis. The conventional four-probe configuration was used and electrodes were made using silver paint.…”

“…9 LuFe 2 O 4 undergoes successive phase transitions. 2D charge correlations are observed below 500 K, while the ferroelectric phase transition is proposed to coincide with a 3D Fe 3+ /Fe 2+ CO below 320 K. 4,5,10 This is followed by ferrimagnetic order below T N ∼ 240 K. 2,[11][12][13] The general claim about ferroelectricity in LuFe 2 O 4 has been based on the following experimental results: (i) the observation of giant dielectric constant at temperatures above 150 K, [4][5][6] and (ii) the measurement of the pyroelectric current after field polarization. 4,5,14 The colossal dielectric properties reported for LuFe 2 O 4 (Refs.…”

Determination of the sequence and magnitude of charge order inLuFe2O4by resonant x-ray scattering

“…The high-temperature crystal structure of LuFe 2 O 4 belongs to the rhombohedral system with space group R3m [30,31] and it is usually described in the hexagonal setting where it can be seen as a stacking of [Fe 2 O 4 shows two phase transitions upon cooling down: first the so-called CO transition ascribed to the ordering of the Fe 3+ and Fe 2+ ions at T CO 320 K [3,5,6] and secondly another transition to a ferrimagnetic ordering that takes place at T C 240 K [32,33]. The CO phase in LuFe 2 O 4 was first characterized by the occurrence of superlattice reflections with (1/3,1/3,l/2) hexagonal Miller indices (from here on, the hexagonal setting is used).…”