The Structural, Anisotropic Magnetization, and Spectroscopic Study of Delafossite CuCr1−x M x O2 Systems

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Evidence of Development of New Spin Orders Benefiting to Enhance Magnetic Properties in Co2+-Doped Delafossite-Type Oxide CuCrO2

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The Structural and Magnetic Properties of CuRh1−x Mn x O2 (0 ≤ x ≤ 0.1) Delafossite Oxide

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Effect of Zn Substitution on the Structural and Physical Properties of Delafossite-Type Oxide CuCrO2

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Structural and magnetoelectric interactions of (Ca, Mg)-doped polycrystalline multiferroic CuFeO< sub> 2</sub>

International audienceIn this work, we investigate crystal structure of delafossite-type oxide CuFe1−x(Ca, Mg)xO2 (0 ≤ x ≤ 0.04). It's known to induce a distortion in the structure, there is an important variation in the two lattice parameters a and c because of the big substitution of biunique radius of Ca2+ and Mg2+ (rCa2+ = 1 Å, rMg2+ = 0.74 Å). Magnetic susceptibility measurements show a magnetic dilution for Ca-doped simples and an amplification of χ with Mg-doping. Temperature dependence of the dielectric permittivity for CuFe1−xMgxO2 present an amplification of ϵ′ at TN2 = 9.1

Structural, Raman Spectroscopy, and Magnetic Ordering in New Delafossite-Type Oxide CuCr1−x Tix O2 (0 ≤ x ≤ 0.1)

International audienceWe investigated in this paper a new mixture +3/+2 B cations delafossites by the doping at Cr3+ sites in CuCrO2 by nonmagnetic cation Ti2+. Ceramics of CuCr1−x Tix O2 (0 ≤ x ≤ 0.1) were prepared via solid state synthesis techniques in a controlled atmosphere of O2. The compound crystallized into the 3R delafossite phase with hexagonal structure. The slightly different size in B cations induced a slightly variation in unit cell parameters. We mod- ulate the spin chirality by the effect of spin dilution for Ti2+ on the structural and magnetic properties of delafos- site CuCrO2 having a S = 3/2 antiferromagnetic triangular lattice (ATL)

The structure, Raman spectroscopy and evidence of ferromagnetic transition in CuCr< sub> 1− x</sub> M< sub> x</sub> O< sub> 2</sub>(M= Mn and Rh) compounds

International audienceThe CuCr1−xMxO2 (M=Mn, Rh) polycrystalline powders were synthesized by the direct solid state reaction of Cu2O and M2O3 (M=trivalent cation or mixer of trivalent cation for transition metal). The magnetic susceptibility was measured in the temperature range of 0-300 K. It was found that the magnetic susceptibility (χ) increases rapidly with the doping of Cr3+ by Mn3+ and Rh3+ ions with existence of paramagnetic substance at low temperature. With the substitution of magnetic Mn3+ and Rh3+ for Cr3+ (S=3/2), the antiferromagnetic (AF) transition becomes broader and the transition temperature increases. However, at low temperature, the magnetic data for CuCr1−xMxO2 (M=Mn, Rh) show evidence for weak ferromagnetic (FM) transition between 100 K and 130 K. Clear hysteresis loops indicate that FM order exists in both of them Mn or Rh-doped samples at 4 K. All samples behave like semiconductors. The ferromagnetism properties can be attributed to the double exchange interaction between the Mn3+ or Rh3+ and Cr3+ semiconductors compounds

Effect of Ga Substitution on the Magnetic State of Delafossite CuCrO2 with Antiferromagnetic Triangular Sublattice

International audienceWe investigated the effect of spin dilution on the structural and magnetic properties of delafossite CuCrO2 having an S=3/2 antiferromagnetic triangular lattice (ATL) by the substitution of Ga3+ for Cr3+ by measurements of magnetization. Spin defects introduced into Cr ATL layers blur the antiferromagnetic transition and induce a dimensional crossover of low-energy magnetic excitation in the residual Cr ATL region due to the reduction of inter-layer magnetic interaction, while accompanying an enhancement of a spin-glass component

Synthesis, structural and magnetic studies of the of the CuCr1-xCoxO2 delafossite oxide

International audienceWe modulate the spin chirality and the magnetization in CuCrO2, by doping at Cr3 þ sites with magnetic ions of slightly different size. Structure and magnetic properties of delafossite oxide CuCr1ﰄxCoxO2 (0 r x r 0.06) have been investigated. With the substitution of magnetic Co3 þ for Cr3 þ (S 1⁄4 3/2), the antiferromagnetic (AF) transition becomes broader and the transition temperature increases. However, at low temperature, the magnetic data for CuCr1ﰄxCoxO2 shows evidence for weak ferromagnetism. Comparing the substitution effect of Co3 þ to those of other magnetic metal transition, magnetization around the AF transition does not seem to correlate with randomness and lattice parameter