Unusual magnetic transition near metal-insulator transition and paramagnetic anomaly in VO2

Yin, Chongyang; Zhang, Run; Qian, Guoyu; Fu, Qingshan; Li, Canglong; Wang, Mingchao; Zhu, Canhong; Wang, Liguang; Yuan, Songliu; Zhao, Xiujian; Tao, Haizheng

doi:10.1063/1.4982589

Cited by 15 publications

(11 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The VO 2 is of paramagnetism for the whole range of temperature covering from high- T metallic to low- T insulating states, which can be confirmed through the measurement of hysteresis loop in which no magnetic hysteresis becomes visible at various fixed temperatures from 370 K to 10 K 28 . Nevertheless, the experimental fact of magnetic transition displayed in Fig.…”

Section: Resultsmentioning

confidence: 62%

“…Below T m,offset the dimers are formed by spin pairing of adjacent V 4+ ions in antiparallel, so that each dimer has no magnetic moment. Therefore, the dimers cannot contribute to the observed low- T paramagnetism, unless that each dimer is phenomenologically assumed to be formed by spin pairing of two V 4+ ions at a T -dependent angle 28 .…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Understanding of metal-insulator transition in VO2 based on experimental and theoretical investigations of magnetic features

Zhang

Yin

et al. 2018

Sci Rep

View full text Add to dashboard Cite

The metal-insulator transition temperature Tc in VO2 is experimentally shown to be almost the same as a magnetic transition temperature Tm characterized by an abrupt decrease in susceptibility, suggesting the evidence of the same underlying origin for both transitions. The measurement of susceptibility shows that it weakly increases on cooling for temperature range of T > Tm, sharply decreases near Tm and then unusually increases on further cooling. A theoretical approach for such unusual observations in susceptibility near Tm or below is performed by modeling electrons from each two adjacent V4+ ions distributed along V-chains as a two-electron system, which indicates that the spin exchange between electrons could cause a level splitting into a singlet (S = 0) level of lower energy and a triplet (S = 1) level of higher energy. The observed abrupt decrease in susceptibility near Tm is explained to be due to that the sample enters the singlet state in which two electrons from adjacent V4+ ions are paired into dimers in spin antiparallel. By considering paramagnetic contribution of unpaired electrons created by the thermal activation from singlet to triplet levels, an expression for susceptibility is proposed to quantitatively explain the unusual temperature-dependent susceptibility observed at low temperatures. Based on the approach to magnetic features, the observed metal-insulator transition is explained to be due to a transition from high-temperature Pauli paramagnetic metallic state of V4+ions to low-temperature dimerized state of strong electronic localization.

show abstract

Section: Resultsmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Understanding of metal-insulator transition in VO2 based on experimental and theoretical investigations of magnetic features

Zhang

Yin

et al. 2018

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Above T N , their relatively weak magnetism is constant with temperature and is attributed to Pauli paramagnetism. 5 Below T N, some recent studies have suggested the possibility of the coexistence of a weak Curie-Weiss paramagnetic behavior with the AF order, such as in strained or doped bulk VO 2 6-8 or V 2 O 3 films and nanoparticles. 9 A ferromagnetic signature was even assumed in some cases, such as VO x nanotubes, [10][11][12] whose origins remain unexplained.…”

mentioning

confidence: 99%

Magnetic phase and magneto-resistive effects in vanadium oxide epitaxial nanoclusters

Kengni-Zanguim

Joly

Scheurer

et al. 2020

Applied Physics Letters

View full text Add to dashboard Cite

The metal-insulator transition and the original magnetic phase that appear in vanadium oxide nanoclusters epitaxially embedded in an MgO matrix are studied via electron transport, magneto-resistance, and X-ray circular dichroism measurements. The metal-insulator transition temperature is observed to be in the range of 1.5-27 K. We observe, from 0.3 K to at least 125 K, a superparamagnetic behavior, whereas vanadium oxide, in its bulk phase, is reported to be anti-ferromagnetic (AF) at low temperatures. This striking feature is consistent with either ferromagnetic spin pairing or spin canting in the AF spin order along the 1D vanadium ion chains of the Magn eli phase or for the VO 2 (A)-like phase. Finally, the observed magneto-resistive effect, which reached up to 8% at low temperatures, indicates ferromagnetic behavior for some of the nanoparticles. This enables their integration in spintronic devices that could be combined with metal-insulator switching and magneto-resistive effects.

show abstract

“…The paired V-V dimers that are formed as zigzag chains arranged in an approaching antiparallel direction, approximately contributing a zero magnetic moment. Besides the paired V-V dimers, some unpaired free V 4+ ions may also be present in the monoclinic [36]. For Zr doped VO 2 samples, the total magnetic moment is given by M total = M dimers + M free + M Zr .…”

Section: Resultsmentioning

confidence: 99%

Effect of Zr Doping on the Magnetic and Phase Transition Properties of VO2 Powder

Wang

et al. 2019

Nanomaterials

View full text Add to dashboard Cite

In this work, V1−xZrxO2 powder (x = 0, 0.01, 0.02, 0.04) was synthesized by two step hydrothermal method. The micro-topography, magnetic and phase transition properties have been investigated using various measurement techniques. All prepared V1−xZrxO2 powder samples exhibit monoclinic structure at room temperature. With the Zr4+ ions doping concentration increased, the shapes of VO2 particles change from spherical to rectangular slice. Besides, the saturation magnetic moment of the samples decrease with the increase of doped Zr4+ ions concentration, while their phase transition temperature increase gradually with Zr ions doping at a rate of around 2 °C/at% on average. We investigated the Zr doping effects on V-V dimers and confirmed the role of V-V dimers in phase transition. We speculate that more V-V dimers form with Zr doping by magnetic measurements, which result in the monoclinic phase of Zr-doped VO2 sample is more stable than rutile phase. Therefore the phase transition temperature is elevated by Zr doping in our experiment. We further consider that the VO2 phase transition should be ascribed to Peierls transition caused by the changing of V-V dimers.

show abstract

Unusual magnetic transition near metal-insulator transition and paramagnetic anomaly in VO2

Cited by 15 publications

References 20 publications

Understanding of metal-insulator transition in VO2 based on experimental and theoretical investigations of magnetic features

Understanding of metal-insulator transition in VO2 based on experimental and theoretical investigations of magnetic features

Magnetic phase and magneto-resistive effects in vanadium oxide epitaxial nanoclusters

Effect of Zr Doping on the Magnetic and Phase Transition Properties of VO2 Powder

Contact Info

Product

Resources

About