Neutron diffraction study of CeMn2Ge2, PrMn2Ge2 and NdMn2Ge2: evidence of dominant antiferromagnetic components within the (001) Mn planes in ferromagnetic ThCr2Si2-type manganese ternary compounds

Welter, Richard; Venturini, G.; Ressouche, E.; Malaman, B.

doi:10.1016/0925-8388(94)01378-0

Cited by 160 publications

(127 citation statements)

References 30 publications

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“…6. This behavior agrees well with the results of Welter et al [27] who demonstrated that in the RMn 2 Ge 2 compounds with R= Pr and Nd, rare earth moments ferromagnetically coupled with the Mn sublattice at low temperatures. This behavior, also applicable to NdMn 2 Si 2 [26] and NdMn 2 Si 1.6 Ge 0.4 [5] compounds, is due to the exchange interaction between the light rare earth elements and 3d transition metal as reported by Coey [28].…”

Section: Resultssupporting

confidence: 82%

Magnetic Properties and Magnetocaloric Effect in Layered NdMn1.9Ti0.1Si2

et al. 2014

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The structural and magnetic properties of the NdMn 1.9 Ti 0.1 Si 2 compund have been studied by high-intensity x-ray and high-resolution neutron powder diffraction, specific heat, dc magnetization, and differential scanning calorimetry measurements over the temperature range of 3-450 K. The Curie temperature and Néel temperature of layered NdMn 1.9 Ti 0.1 Si 2 are indicated as T C ~ 22 K and T N ~ 374 K respectively. The first order magnetic transition from antiferromagnetic [AFil-type] to ferromagnetic [F(Nd)+Fmc] around T C is found in layered NdMn 1.9 Ti 0.1 Si 2 and is associated with large magnetocaloric effect. This behavior has been confirmed as a contribution of the magnetostructural coupling by using neutron and x-ray powder diffraction. The magnetic entropy change -ΔS M ~ 15.3 J kg -1 K -1 and adiabatic temperature change ΔT ad ~ 4.7 K have been determined using magnetization and specific heat measurement under 0-5 T applied fields. This compound exhibits almost no thermal and magnetic hysteresis, thus potentially applicable in low temperature region for magnetic refrigerator material.

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Section: Resultssupporting

confidence: 82%

Magnetic Properties and Magnetocaloric Effect in Layered NdMn1.9Ti0.1Si2

et al. 2014

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“…Such transitions were detected in RMn 2 Ge 2 compounds (where R is La, Ce, Pr and Nd) [10,12]. The compound PrMn 2 Ge 2 , is studied well (see for example the references [3,4,[14][15][16]) and we now know from the literature that intralayer in-plane antiferromagnetic ordering (AFl) occurs below the Néel temperature T N =415 K. Cooling to temperatures below the Curie temperature T C =330 K leads to a canted spin structure (Fmc) with the c-axis interlayer spin components aligning parallel.…”

Section: Introductionmentioning

confidence: 95%

“…The nature of the magnetic coupling within and between the Mn layers in these compounds is closely related to the in-plane Mn-Mn spacing a Mn Mn d − . A detailed discussion of the magnetic behavior as a function of Mn-Mn spacing were given in previous publications [9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

XRD, AC susceptibility and DSC studies of PrMn _2–x Ni _x Ge ₂ compounds

Kervan

Kılıç

Gençer

2004

phys. stat. sol. (c)

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PACS 61.66.Fn, 75.30.Cr, 75.50.-y X-ray powder diffraction, AC susceptibility and differential scanning calorimetry (DSC) studies were performed on the polycrystalline PrMn 2-x Ni x Ge 2 (0≤x≤1) compounds. Substitution of Ni for Mn leads a linear decrease in the lattice constant c and the unit cell volume, while it gives rise a change of magnetic properties from ferromagnetic to anti-ferromagnetic behavior for small values of x<1. The samples with x=0.8 and 1.0 have a Néel temperature of about 33 K and 35 K, respectively. The samples with low Ni concentration are ferromagnetic and show an additional increase in the susceptibility. The substitution of nonmagnetic Ni for Mn weakens strength of the molecular field acting on Mn layers, yielding decrease of Curie temperature. The results lead to the construction of the partial x-T magnetic phase diagram.

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“…7. Concerning the S of Mn, now both ab initio calculations [7,12] and experimental results [2,5] give a magnetic moment near to 5 2 µ B , which by Landé formula and for a quenched orbital momentum gives a total angular momentum (denoted S in this work) equal to 1. In this case no conical structure is obtained for our Hamiltonian.…”

Section: Numerical Calculations Lamn2ge2mentioning

confidence: 99%

“…The experimental values reported in ref. 5 are T c1 = 45 K and T c2 = 305 K (the T > 305 K region is not studied therein).…”

Section: Numerical Calculations Lamn2ge2mentioning

confidence: 99%

Transitions involving conical magnetic phases in a model with bilinear and biquadratic interactions

Massidda

2008

Journal of Magnetism and Magnetic Materials

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In a previous work a model was proposed for the phase transitions of crystals with localized magnetic moments which at low temperature have a "conical" arrangement that at higher T transforms into a more symmetrical structure (depending on the compound) before becoming totally disordered. The model assumes bilinear and biquadratic interactions between magnetic moments up to the fifth neighbours, and for any given T the structure with the least free energy is obtained by a mean-field approximation (MFA). The interaction constants are derived from ab initio energy calculations.In this work we improve upon that model modifying the MFA in such a way that a continuous (instead of discontinuous) spectrum of excited states is available to the system. In the previous work, which dealt with LaMn2Ge2 and LaMn2Si2, we found that transitions to different structures can be obtained for increasing T , in good qualitative agreement with experiment. The critical temperatures, however, were exaggerately high. With the new MFA we obtain essentially the same behaviour concerning the phase transitions, and critical temperatures much closer to the experimental ones.

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Neutron diffraction study of CeMn2Ge2, PrMn2Ge2 and NdMn2Ge2: evidence of dominant antiferromagnetic components within the (001) Mn planes in ferromagnetic ThCr2Si2-type manganese ternary compounds

Cited by 160 publications

References 30 publications

Magnetic Properties and Magnetocaloric Effect in Layered NdMn<sub>1.9</sub>Ti<sub>0.1</sub>Si<sub>2</sub>

Magnetic Properties and Magnetocaloric Effect in Layered NdMn<sub>1.9</sub>Ti<sub>0.1</sub>Si<sub>2</sub>

XRD, AC susceptibility and DSC studies of PrMn _2–x Ni _x Ge ₂ compounds

Transitions involving conical magnetic phases in a model with bilinear and biquadratic interactions

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Neutron diffraction study of CeMn2Ge2, PrMn2Ge2 and NdMn2Ge2: evidence of dominant antiferromagnetic components within the (001) Mn planes in ferromagnetic ThCr2Si2-type manganese ternary compounds

Cited by 160 publications

References 30 publications

Magnetic Properties and Magnetocaloric Effect in Layered NdMn<sub>1.9</sub>Ti<sub>0.1</sub>Si<sub>2</sub>

Magnetic Properties and Magnetocaloric Effect in Layered NdMn<sub>1.9</sub>Ti<sub>0.1</sub>Si<sub>2</sub>

XRD, AC susceptibility and DSC studies of PrMn 2–x Ni x Ge 2 compounds

Transitions involving conical magnetic phases in a model with bilinear and biquadratic interactions

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XRD, AC susceptibility and DSC studies of PrMn _2–x Ni _x Ge ₂ compounds