Metamagnetic transition in Y2Cu2O5

Motokawa, M.; Kita, K.; Shibazaki, H.; Ohta, H.; Jang, Wen-Jye; Hasegawa, Masashi; Takei, Hiroyuki

doi:10.1016/0921-4526(94)00975-2

Cited by 15 publications

(13 citation statements)

References 3 publications

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“…However, the slope of the magnetization above 13 T for B//c does not coincide with the slope of that for B⊥c, while they usually coincide for the typical S=1/2 two sublattice antiferromagnet because the single ion type anisotropy is not expected in the S=1/2 system. However, such a deviation in the magnetization was also observed in Y 2 Cu 2 O 5 [4], and it was interpreted by the consideration of the multi-sublattice model [5]. Moreover, the magnetization result of dioptase seems to coincide with the fact that our AFMR results at 1.8 K start to deviate from the AFMR modes calculated by the two sublattice molecular field theory [6,7] above B c for B//c [2].…”

Section: Methodsmentioning

confidence: 87%

Magnetic susceptibility measurement under high pressure and magnetization measurement of S = 1/2 dioptase lattice antiferromagnet

Ohta

Fujisawa

Souda

et al. 2009

J. Phys.: Conf. Ser.

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Abstract. Natural mineral Dioptase (Cu6Si6O18 · 6H2O) is an S=1/2 antiferromagnet with a unique spin network which consists of helical chains along the c axis connected by inter chain exchange interactions. In order to study the ground state of dioptase, we have performed the magnetization measurement for B//c (easy axis) at 1.5 K and have found the spin-flop transition at 13 T. Moreover, the pressure effect of the magnetic susceptibility is investigated up to 1.78 GPa using the SQUID magnetometer where TN increased while the broad maximum reflecting the low dimensionality of the system decreased by pressure. The results will be discussed in connection with our previous antiferromagnetic resonance (AFMR) measurement results and the phase diagram obtained by Gros et al. IntroductionNatural mineral Dioptase (Cu 6 Si 6 O 18 · 6H 2 O) is a unique S=1/2 antiferromagnet where Cu 2+ ions form the antiferromagnetic helical chain along the c-axis (the exchange interaction J 2 = J(1 − δ) and the chains are antiferromagnetically connected (the exchange interaction. This unique spin network is called the dioptase lattice and the phase diagram of its ground state is obtained by the Quantum Monte Carlo calculation [1]. As shown in Fig. 1 the calculation suggests that the quantum critical point at δ =0.3 is expected in between the antiferromagnetic order phase (δ <0.3) and the spin gap phase (δ >0.3) [1]. However, the magnetic susceptibility of dioptase shows a broad maximum around 45 K and the antiferromagnetic order is observed at T N =15.5 K. Its analysis by the Quantum Monte Carlo calculation suggest δ =0.1, J=56.6 K, g=2.09 or δ =-0.1, J=53.4 K, g=2.10 for dioptase [1]. Moreover, our previous high field ESR result at 1.8 K clearly shows the existence of antiferromagnetic order below T N by the observation of AFMR, and the existence of the spin-flop

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Section: Methodsmentioning

confidence: 87%

Magnetic susceptibility measurement under high pressure and magnetization measurement of S = 1/2 dioptase lattice antiferromagnet

Ohta

Fujisawa

Souda

et al. 2009

J. Phys.: Conf. Ser.

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“…2 For the cooling run, below 100 K, the magnetic moment starts to increase significantly, indicative of strong ferromagnetic interactions. This situation could be explained by application of a model used previously to clarify the appearance of metamagnetic transitions in the antiferromagnetic phase of the R 2 Cu 2 O 5 compounds [18][19][20]. The model is essentially the molecularfield theory which assumes pairing of two neighbouring Cu 2+ spins in the copper chain along the a-axis.…”

Section: Resultsmentioning

confidence: 98%

“…Special attention will be paid to the interpretation of thermal dependence of EPR susceptibility χ EPR and the product χ EPR T, which reflects the effective magnetic moment. The obtained results will be interpreted in terms of a model proposed previously to interpret the antiferromagnetic resonance spectra [18].…”

Section: Introductionmentioning

confidence: 96%

Competing interactions and dimensional crossover in (Er0.5Y0.5)2Cu2O5 studied by EPR

Typek

2007

Journal of Alloys and Compounds

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“…To explain the appearance of metamagnetic transitions in the antiferromagnetic phase of the R 2 Cu 2 O 5 compounds a model has been proposed assuming pairing of two neighbouring Cu 2+ spins in the copper chain along the a-axis [11][12][13]. This way chains of copper dimers S = 1 is formed, which are aligned ferromagnetically.…”

Section: Originalmentioning

confidence: 98%

“…The EPR results will be interpreted in frame of a model used previously to explain the metamagnetic transitions in the antiferromagnetic phase of the R 2 Cu 2 O 5 compounds [11][12][13]. …”

Section: Originalmentioning

confidence: 99%

Competing magnetic interactions in (Dy_0.375Y_0.625)₂Cu₂O₅ solid solution studied by EPR

Typek

2007

Physica Status Solidi (b)

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structure has been found in the EPR spectrum and the values of appropriate exchange constants connected with a hierarchy of exchange interactions has been calculated. At about 40 K a dimensional crossover from 2D to 3D behaviour has been observed in the temperature dependence of the product of the EPR integrated intensity and temperature. At high temperatures (T > 200 K) the EPR spectrum is suggestive of the presence of defect centres consisting of antferromagnetically coupled copper spins, forming dimers with the S = 0 ground state.

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Metamagnetic transition in Y2Cu2O5

Cited by 15 publications

References 3 publications

Magnetic susceptibility measurement under high pressure and magnetization measurement of S = 1/2 dioptase lattice antiferromagnet

Magnetic susceptibility measurement under high pressure and magnetization measurement of S = 1/2 dioptase lattice antiferromagnet

Competing interactions and dimensional crossover in (Er0.5Y0.5)2Cu2O5 studied by EPR

Competing magnetic interactions in (Dy_0.375Y_0.625)₂Cu₂O₅ solid solution studied by EPR

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Metamagnetic transition in Y2Cu2O5

Cited by 15 publications

References 3 publications

Magnetic susceptibility measurement under high pressure and magnetization measurement of S = 1/2 dioptase lattice antiferromagnet

Magnetic susceptibility measurement under high pressure and magnetization measurement of S = 1/2 dioptase lattice antiferromagnet

Competing interactions and dimensional crossover in (Er0.5Y0.5)2Cu2O5 studied by EPR

Competing magnetic interactions in (Dy0.375Y0.625)2Cu2O5 solid solution studied by EPR

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Competing magnetic interactions in (Dy_0.375Y_0.625)₂Cu₂O₅ solid solution studied by EPR