Thermodynamic properties of the ternary compounds CeM2Ge2

Böhm, A.; Caspary, R.; Habel, U.; Pawlak, L.; Zuber, A.; Steglich, F.; Loidl, A.

doi:10.1016/0304-8853(88)90347-2

Cited by 62 publications

(20 citation statements)

References 6 publications

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“…3 The CeRu 2 (Ge 1−x Si x ) 2 system, where the Si atoms are substituted for the Ge atoms of CeRu 2 Ge 2 with the tetragonal ThCr 2 Si 2 structure, is a good example of the system describable within the Doniach phase diagram. CeRu 2 Ge 2 shows a ferromagnetic order below the Curie temperature T C ≈ 7.5 K. 4,5 The Ce 4f electrons of CeRu 2 Ge 2 are considered to be localized, because the Fermi surfaces obtained from the de Haas-van Alphen (dHvA) and angle-resolved photoelectron spectroscopy (ARPES) experiments [6][7][8] are consistent with the theoretically obtained Fermi surfaces including no 4f electrons. 9 The magnetic order turns from ferromagnetic to antiferromagnetic with the substitution of the Si atoms for the Ge atoms, i.e., increase of x in CeRu 2 (Ge 1−x Si x ) 2 , and it vanishes above the critical composition x c ≈ 0.93.…”

Section: Introductionmentioning

confidence: 60%

Magnetic behavior near the boundary of4fdelocalization in ferromagnetic CeRu2Ge2and paramagnetic CeRu

et al. 2012

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X-ray absorption (XAS) and its magnetic circular dichroism (XMCD) were measured at the Ce M 4,5 absorption edges of ferromagnetic CeRu 2 Ge 2 and paramagnetic CeRu 2 Si 2 : both compounds are considered to be located near the boundary of delocalization of Ce 4f electrons. While the XAS line shape varies clearly reflecting the variation in the 4f delocalization, the line-shape variation in XMCD is hardly discernible under various conditions of temperature and magnetic field. The XAS line-shape variation can be explained as effects of the variations in the 4f occupation number and in the ratio of J = 7/2 states in the ground states, both of which are closely related to the 4f delocalization. The 4f delocalization also causes a decrease in the ratio of the orbital magnetic moment to the spin magnetic moment. The magnetic-field dependence of XAS suggests that the Ce 4f electrons retain a delocalized character across the metamagnetic transition in CeRu 2 Si 2 .

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Section: Introductionmentioning

confidence: 60%

Magnetic behavior near the boundary of4fdelocalization in ferromagnetic CeRu2Ge2and paramagnetic CeRu

et al. 2012

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“…1͒, close to the theoretical value S/Rϭln 2ϭ0.69, expected for Sϭ1/2 spin magnetism. It is noted that the former S/R value is found in literature 6,8,9,26 regardless of the height of the FM peak and the occurrence of the AFM order.…”

Section: A Ambient Pressure Propertiesmentioning

confidence: 77%

Detailed investigation of the magnetic phase diagram ofCeRu2Ge2up to 11 GPa

et al. 1999

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The electrical resistivity (T) and transverse magnetoresistivity of magnetically ordered CeRu 2 Ge 2 (T N ϭ8.55 K and T C ϭ7.40 K) was measured as a function of pressure up to Pϭ11 GPa and down to Tϭ30 mK. Pressure first increases T N and suppresses T C. Then a second transition, corresponding probably to a modification of the AFM state, appears at T L ϽT N in the pressure range 3.5Ͻ PϽ7.2 GPa. The long-range magnetic order disappears at a critical pressure P c ϭ8.7 GPa like T N ϰ(P c Ϫ P) m , with mϭ0.71(8). The (T) curves at low temperature and low pressure (PϽ7.8 GPa) are well described by a power law (T)ϰT n , with exponents nϾ2. Well above P c , a Fermi liquid behavior (nϭ2) is observed and the A coefficient of the quadratic T dependence decreases with pressure. In the pressure interval P c Ϯ0.8 GPa, exponents close to n ϭ1.5 indicate a deviation from a Fermi liquid description. The magnetoresistivity curves show different anomalies at characteristic magnetic fields B a , B c , and B M. The latter occurs close to P c and is reminiscent of the metamagneticlike field in CeRu 2 Si 2. A quantitative comparison between the (T, P) data of CeRu 2 Ge 2 and the (T,x) data of CeRu 2 (Si 1Ϫx Ge x) 2 on the basis of the unit-cell volume as the crucial parameter shows that the same (T,V) diagram is obtained. ͓S0163-1829͑99͒05705-7͔

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“…In field the curvature in C/T enhances significantly. At H = 80 kOe our fitting procedure results in a larger value for a sw , whereas the spin wave contribution should be suppressed under magnetic field, as for instance in Ni [32] and CeRu 2 Ge 2 [33]. This strongly suggests that the low temperature variation in C(T)/T is not due to a ferromagnetic spin-wave contribution.…”

Section: F Specific Heatmentioning

confidence: 79%

“…32͒ and CeRu 2 Ge 2 . 33 This strongly suggests that the low-temperature variation in C͑T͒ / T is not due to a ferromagnetic spin-wave contribution.…”

Section: F Specific Heatmentioning

confidence: 92%

Weak itinerant ferromagnetism in Heusler-typeFe2VAl0.95

et al. 2010

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Weak itinerant ferromagnetism in Sato, K.; Naka, T.; Taguchi, M.; Nakane, T.; Ishikawa, F.; Yamada, Y.; Takaesu, Y.; Nakama, T.; de Visser, A.; Matsushita, A. Published in:Physical Review B DOI:10.1103/PhysRevB.82.104408 Link to publicationCitation for published version (APA): Sato, K., Naka, T., Taguchi, M., Nakane, T., Ishikawa, F., Yamada, Y., ... Matsushita, A. (2010 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. We report measurements of the magnetic, transport, and thermal properties of the Heusler-type compound Fe 2 VAl 0.95 . We show that while stoichiometric Fe 2 VAl is a nonmagnetic semimetal a 5% substitution on the Al site with the 3d elements Fe and V atoms leads to a ferromagnetic ground state with a Curie temperature T C =33Ϯ 3 K and a small ordered moment s = 0.12 B / Fe in Fe 2 VAl 0.95 . The reduced value of the ratio s / p = 0.08, where p = 1.4 B / Fe is the effective Curie-Weiss moment, together with the analysis of the magnetization data M͑H , T͒, show magnetism is of itinerant nature. The specific heat shows an unusual temperature variation at low temperatures with an enhanced Sommerfeld coefficient, ␥ =12 mJ K −2 mol −1 . The resistivity, ͑T͒, is metallic and follows a power law behavior = 0 + AT n with n Ϸ 1.5 below T C . With applying pressure, T C decreases with the rate of ͑1 / T C ͒͑dT C / dP͒ = −0.061 GPa −1 . We conclude substitution on the Al site with Fe and V atoms results in itinerant ferromagnetism with a low carrier density.

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Thermodynamic properties of the ternary compounds CeM2Ge2

Cited by 62 publications

References 6 publications

Magnetic behavior near the boundary of4fdelocalization in ferromagnetic CeRu2Ge2and paramagnetic CeRu

Magnetic behavior near the boundary of4fdelocalization in ferromagnetic CeRu2Ge2and paramagnetic CeRu

Detailed investigation of the magnetic phase diagram ofCeRu2Ge2up to 11 GPa

Weak itinerant ferromagnetism in Heusler-typeFe2VAl0.95

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