Correlation between the negative magnetoresistance effect and magnon excitations in single-crystalline CuCr1.6V0.4Se4

Malicka, E.; Groń, T.; Skrzypek, D.; Pacyna, A.W.; Badurski, D.; Waśkowska, A.; Mazur, S.; Sitko, Rafał

doi:10.1080/14786430903405504

Cited by 10 publications

(4 citation statements)

References 34 publications

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“…In the extrinsic region (77–125 K), the activation of electrical conductivity was not observed ( Figure 5 ). The influence of anisotropy on the value of electrical resistivity in the studied spinel single crystals was not observed, as in the CuCr 1.6 V 0.4 Se 4 spinel single crystal, in which the resistance was measured in the direction of [001] and [111] [ 28 ].…”

Section: Resultsmentioning

confidence: 99%

Study of the Structure, Magnetic, Thermal and Electrical Characterisation of ZnCr2Se4: Ta Single Crystals Obtained by Chemical Vapour Transport

et al. 2021

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The new series of single-crystalline chromium selenides, Ta-doped ZnCr2Se4, was synthesised by a chemical vapour transport method to determine the impact of a dopant on the structural and thermodynamic properties of the parent compound. We present comprehensive investigations of structural, electrical transport, magnetic, and specific heat properties. It was expected that a partial replacement of Cr ions by a more significant Ta one would lead to a change in direct magnetic interactions between Cr magnetic moments and result in a change in the magnetic ground state and electric transport properties of the ZnCr2−xTaxSe4 (x = 0.05, 0.06, 0.07, 0.08, 0.1, 0.12) system. We found that all the elements of the cubic system had a cubic spinel structure; however, the doping gain linearly increased the ZnCr2−xTaxSe4 unit cell volume. Doping with tantalum did not significantly change the semiconductor and magnetic properties of ZnCr2Se4. For all studied samples (0 ≤ x ≤ 0.12), an antiferromagnetic order (AFM) below TN~22 K was observed. However, a small amount of Ta significantly reduced the second critical field (Hc2) from 65 kOe for x = 0.0 (ZnCr2Se4 matrix) up to 42.2 kOe for x = 0.12, above which the spin helical system changed to ferromagnetic (FM). The Hc2 reduction can lead to strong competition among AFM and FM interactions and spin frustration, as the specific heat under magnetic fields H < Hc2 shows a strong field decrease in TN.

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Section: Resultsmentioning

confidence: 99%

Study of the Structure, Magnetic, Thermal and Electrical Characterisation of ZnCr2Se4: Ta Single Crystals Obtained by Chemical Vapour Transport

et al. 2021

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“…The results of μ-XRF analysis obtained by using the standardless FP method were compared with those resulting from ICP-OES and WDXRF, requiring the sample digestion. For this purpose, the measurements were done for several crystals of ZnCr 2 Se 4 , CdCr 2 Se 4 , and CuCr 2 Se 4 doped with V, Ga, In, and Cd [ 15 – 18 ]. The agreement between the results appears to be quite good, as the relative differences in the analyses do not exceed 5%.…”

Section: Resultsmentioning

confidence: 99%

Nondestructive analysis of single crystals of selenide spinels by X-ray spectrometry techniques

et al. 2010

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The paper presents possibilities and difficulties in nondestructive analysis of small multielement single crystals performed by means of X-ray spectrometry techniques: micro-X-ray fluorescence spectrometry (μ-XRF), energy-dispersive electron probe microanalysis (ED-EPMA), and X-ray photoelectron spectroscopy (XPS). The capability of the X-ray spectroscopy techniques in elemental analysis is demonstrated with the single crystals of selenide spinels of the general formula MxNyCrzSe4 (M+2 and N+3 are, for example, Zn+2, V+3, Ga+3, Cd+2, In+3, and Sb+3). The results of the nondestructive analyses (μ-XRF, ED-EPMA, and XPS) are compared with those obtained by inductively coupled plasma optical emission spectrometry (ICP-OES) and wavelength-dispersive X-ray spectrometry (WDXRF) following sample digestion. The present study shows satisfactory agreement between the results of μ-XRF analysis performed using the standardless fundamental parameter method and the results obtained with the WDXRF and ICP-OES analyses. If the measured single crystal is precisely positioned, the difference between μ-XRF and wet analysis (WDXRF and ICP-OES) does not exceed 5% rel. The reliable results of ED-EPMA can be obtained only if the measured area is sufficiently large, i.e., of 200 × 300 μm. Even if this condition is fulfilled, the relative difference between the ED-EPMA and the wet analysis may reach 10% rel. In case of the XPS analysis, the accuracy of results depends on the proper preparation of the sample surface. It should be free of contamination that can be obtained by scraping in situ in ultrahigh vacuum. The ion etching, commonly used for cleaning the surface, leads to preferential sputtering; therefore, the reliable results cannot be obtained.FigureThe paper presents possibilities and difficulties in nondestructive analysis of small multielement single crystals performed by means of X-ray spectrometry techniques: micro-XRF, ED-EPMA and XPS.

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“…Thus, the double exchange mechanism tends to align the site spins ferromagnetically [33]. The theoretical procedure for calculating the exchange integrals according to the Lotgering model [30] has already been described many times in works [29,35,36] and was used to calculate these integrals of the investigated nanopinel (Table 7 includes a bulk spinel for comparison) in order to interpret its electrical and magnetic properties. x 3 and x 4 are the portions of the Cr 3+ and Cr 4+ ions, respectively, X is the mixture of spins due to the presence of chromium ions, θ se is the superexchange contribution to θ, θ de is the double exchange contribution to θ, B is the total hopping integral for the first and second coordination spheres, W d is the mixed valence (Cr 3+ ,Cr 4+ ) bandwidth, J aa and J ab , b aa and b ab , and J aa eff and J ab eff are the superexchange, double exchange, and effective integrals for the first two coordination spheres, respectively.…”

Section: Discussionmentioning

confidence: 99%

Magnetic and Electrical Properties of CuCr2Se4 Nanoparticles

Malicka,

Groń,

Gudwański

et al. 2023

Materials

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CuCr2Se4 nanoparticles were obtained by the high-energy ball milling of CuCr2Se4 single crystals, which had a size of approximately 32 nm after 5 h of milling. Structural, magnetic, and electrical studies have shown that a reduction in CuCr2Se4 single crystals to the nanosize leads to (1) a weakening of ferromagnetic interactions, both long and short range, (2) a lack of saturation of magnetization at 5 K and 70 kOe, (3) a change in the nature of electrical conductivity from metallic to semiconductor, and (4) a reduction in the thermoelectric power factor S2σ by an order of magnitude of 400 K. The above results were considered in terms of the parameters of the band model, derived from the high-temperature expansion of magnetic susceptibility and from the diffusive component of thermoelectric power. Theoretical calculations showed a significant weakening of both the superexchange and double exchange mechanisms, a reduction in the [Cr3+,Cr4+] band width from 0.76 to 0.19 eV, and comparable values of the Fermi energy and the activation energy (0.46 eV) in the intrinsic region of electrical conductivity. The main advantage of high-energy ball milling is the ability to modify the physicochemical properties of already existing compounds for desired applications.

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Correlation between the negative magnetoresistance effect and magnon excitations in single-crystalline CuCr_1.6V_0.4Se₄

Cited by 10 publications

References 34 publications

Study of the Structure, Magnetic, Thermal and Electrical Characterisation of ZnCr2Se4: Ta Single Crystals Obtained by Chemical Vapour Transport

Study of the Structure, Magnetic, Thermal and Electrical Characterisation of ZnCr2Se4: Ta Single Crystals Obtained by Chemical Vapour Transport

Nondestructive analysis of single crystals of selenide spinels by X-ray spectrometry techniques

Magnetic and Electrical Properties of CuCr2Se4 Nanoparticles

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