Magnetic ground state and exchange interactions in the Ising chain ferromagnet 
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Thota, Subhash; Ghosh, Sayandeep; Maruthi, R; Joshi, D. C.; Medwal, Rohit; Rawat, Rajdeep Singh; Seehra, M. S.

doi:10.1103/physrevb.103.064415

Cited by 21 publications

(24 citation statements)

References 32 publications

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“…The phase diagram in figure 9 with triple point T TP (H, T) = (18 kOe, 4.06 K) is qualitatively similar to that reported in the uniaxial antiferromagnet MnF 2 [25][26][27]. This is an important result of this work because of its resemblance to the H-T phase diagram in MnF 2 and drastic differences from the H-T phase diagram of CoNb 2 O 6 [14].…”

Section: H-t Phase Diagramsupporting

confidence: 80%

“…For NiNb 2 O 6 , the studies by Yaeger et al [4], Heid et al [6] and Sarvezuk et al [7] reported T N = 5.7 K with easy direction being closer to c-axis. The magnetic properties of CoNb 2 O 6 are somewhat different in that it is shown to be a good example of an Ising chain ferromagnet along the c-axis with effective spin S = 1/2 and exchange constant J 0 /k B = 6.2 K and the interchain antiferromagnetic exchange constants J 1 /k B = −0.42 K and J 2 /k B = −0.67 K [14]. The Co 2+ moments are aligned close to c-axis with canting angle φ = ±31 • .…”

Section: Introductionmentioning

confidence: 99%

“…A schematic diagram of this structure based on available literature [1][2][3][4][5][6][7][8][9][10][11][12][13] is shown in figure 1. Consequently, the Hamiltonian describing the exchange coupling among M 2+ ions in these systems can be written as [6,7,13,14]:…”

Section: Introductionmentioning

confidence: 99%

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Magnetic field-temperature phase diagram, exchange constants and specific heat exponents of the antiferromagnet MnNb₂O₆

Maruthi¹,

Ghosh²,

Seehra³

et al. 2021

J. Phys.: Condens. Matter

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This work presents the magnetic field-temperature (H-T) phase diagram, exchange constants, specific heat (C P ) exponents and magnetic ground state of the antiferromagnetic MnNb 2 O 6 polycrystals. Temperature dependence of the magnetic susceptibility χ (= M/H) yields the Néel temperature T N = 4.33 K determined from the peak in the computed ∂(χT)/∂T vs T plot in agreement with the transition in the C P vs T data at T N = 4.36 K. The experimental data of C P vs T near T N is fitted to C P = A|T − T N | −α yielding the critical exponent α = 0.12(0.15) for T > T N (T < T N ). The best fit of χ vs T data for T > 50 K to χ = χ 0 + C/(T − θ) with χ 0 = −1.85 × 10 −4 emu mol −1 Oe −1 yields θ = −17 K, and C = 4.385 emu K mol −1 Oe −1 , the latter giving magnetic moment μ = 5.920μ B per Mn 2+ ion. This confirms the effective spin S = 5/2 and g = 2.001 for Mn 2+ and the dominant exchange interaction being antiferromagnetic in nature. Using the magnitudes of θ and T N and molecular field theory (MFT), the exchange constants J 0 /k B = −1.08 K for Mn 2+ ions along the chain c-axis and J ⊥ /k B = −0.61 K as the interchain coupling perpendicular to c-axis are determined. These exchange constants are consistent with the expected χ vs T variation for the Heisenberg linear chain. The H-T phase diagram, mapped using the M-H isotherms and M-T data at different H combined with the reported data of Nielsen et al, yields a triple-point T TP (H, T) = (18 kOe, 4.06 K). The spin-flopped state above T TP and the forced ferromagnetism for H > 192 kOe are used to estimate the anisotropy energy H A ≈ 0.8 kOe.

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Section: H-t Phase Diagramsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

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Magnetic field-temperature phase diagram, exchange constants and specific heat exponents of the antiferromagnet MnNb₂O₆

Maruthi¹,

Ghosh²,

Seehra³

et al. 2021

J. Phys.: Condens. Matter

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“…For

T ≪ T_{normalN}

, NPD and saturation magnetization

M_{normals} =

N_{normalA} g S {normalμ}_{normalB} = N_{normalA} {normalμ}_{z}

measure the z ‐component of the magnetization. Additional discussion on this distinction between μ and

{normalμ}_{z}

is given in previous studies [26,28,34‐36]. The rich spin states of Co 2+ in different coordination environments have challenged the theoretical simulation of the magnetic properties of cobalt compounds because both S = 1 / 2 and S = 3 / 2 are possible ground states for Co 2+ ions under proper conditions.…”

Section: Resultsmentioning

confidence: 99%

“…One of the interesting recent examples of the interplay of the various factors mentioned above in the magnetic properties is the transverse Ising magnet CoNb 2 O 6 with the effective spin S = ½ ground state in which observation of quantum critical point has been reported. [ 27,28 ] Another example is the linear chain antiferromagnet Co(OH) (2− x ) F x whose magnetic properties along with the details of the synthesis of the samples and their structural characterization using X‐ray and neutron diffraction techniques have been reported in the recent articles by Yahia et al [ 29 ] and Liu et al [ 30 ] The octahedra in Co(OH) (2− x ) F x is distorted because of the F substitution effects on the O site and the involvement of –OH. They discussed the magnetism of Co(OH) (2− x ) F x based on the assumption of the spin state of Co 2+ in octahedral CoO 6 crystal field as

S =

3 / 2 .…”

Section: Introductionmentioning

confidence: 99%

Magnetic Ground State and Tunable Néel Temperature in the Spin ½ Linear Chain Antiferromagnet Co(OH)_(2−x)F_x

Zhang

Liu

et al. 2022

Physica Status Solidi (b)

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The ground state of Co2+ in the octahedral CoO6 crystal field has often been assumed to be in high spin state with S = 3/2. As a result, the effective magnetic moments of Co2+ are overestimated in Co(OH)(2−x)F x . Herein, it is argued that the ground state of Co2+ in Co(OH)(2−x)F x has effective spin 1/2 but not S = 3/2, due to spin–orbit coupling in distorted octahedral crystal field. Analysis of the published magnetic susceptibility (χ) data on three samples of Co(OH)(2−x)F x is reported here with the new result that the Néel temperature T N decreases with an increase in χ as T N = 36.5, 30.5, and 26.5 K are determined for x = 1.09, 1.14, and 1.26, respectively. The employment of modified Curie–Weiss (CW) law along with S = 1/2 ground state eliminates the reported disagreement between the magnetic moment μ(Co2+) obtained from CW law above and neutron powder diffraction (NPD) below The fits of the data to the predictions of the linear chain model yield the exchange constant J/k B = −30.5, −28.1, and −24.7 K for x = 1.09, 1.14, and 1.26, respectively, supporting the chain‐like antiferromagnetic ordering observed using NPD.

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Magnetic Properties of La0.81Sr0.19Mn0.9Fe0.1−xZnxO3 (x = 0, x = 0.05)

et al. 2022

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Magnetic properties of polycrystalline La 0.81 Sr 0.19 Mn 0.9 Fe 0.1−𝑥 Zn 𝑥 O 3 (𝑥 = 0, 0.05) have been investigated by means of electron spin resonance, magnetic susceptibility, and Mössbauer measurements. Both samples show a clear ferromagnetic transition. The Curie temperature 𝑇 C decreases on increasing Fe content. Mössbauer studies indicate that Fe in these compounds is in the trivalent high-spin state. The temperature evolution of the Mössbauer spectra at low temperatures (𝑇 < 𝑇 C ) is typical for ferromagnetic clusters with a wide distribution in size and magnetic correlation length. The inverse susceptibility of all the samples deviates from the Curie-Weiss law above 𝑇 C , indicating the presence of uctuations on approaching magnetic order. An anomalous downturn of the inverse susceptibility for 𝑥 = 0.05 signi cantly above 𝑇 C and the concomitant observation of ferromagnetic resonance signals coexisting with the paramagnetic resonance up to approximately room temperature, is caused by a Gri ths-like behavior. This regime is characterized by the coexistence of ferromagnetic entities within the globally paramagnetic phase.

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Magnetic ground state and exchange interactions in the Ising chain ferromagnet CoNb2O6

Cited by 21 publications

References 32 publications

Magnetic field-temperature phase diagram, exchange constants and specific heat exponents of the antiferromagnet MnNb₂O₆

Magnetic field-temperature phase diagram, exchange constants and specific heat exponents of the antiferromagnet MnNb₂O₆

Magnetic Ground State and Tunable Néel Temperature in the Spin ½ Linear Chain Antiferromagnet Co(OH)_(2−x)F_x

Magnetic Properties of La0.81Sr0.19Mn0.9Fe0.1−xZnxO3 (x = 0, x = 0.05)

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Magnetic ground state and exchange interactions in the Ising chain ferromagnet CoNb2O6

Cited by 21 publications

References 32 publications

Magnetic field-temperature phase diagram, exchange constants and specific heat exponents of the antiferromagnet MnNb2O6

Magnetic field-temperature phase diagram, exchange constants and specific heat exponents of the antiferromagnet MnNb2O6

Magnetic Ground State and Tunable Néel Temperature in the Spin ½ Linear Chain Antiferromagnet Co(OH)(2−x)Fx

Magnetic Properties of La0.81Sr0.19Mn0.9Fe0.1−xZnxO3 (x = 0, x = 0.05)

Contact Info

Product

Resources

About

Magnetic field-temperature phase diagram, exchange constants and specific heat exponents of the antiferromagnet MnNb₂O₆

Magnetic field-temperature phase diagram, exchange constants and specific heat exponents of the antiferromagnet MnNb₂O₆

Magnetic Ground State and Tunable Néel Temperature in the Spin ½ Linear Chain Antiferromagnet Co(OH)_(2−x)F_x