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Antonio, D.; Dolz, M.I.; Pastoriza, H. | ||||
| Title | Magnetization measurement of single La0.67Ca0.33MnO3 nanotubes in perpendicular magnetic fields using a micromechanical torsional oscillator | Type | Journal Article | ||
| Year | 2010 | Publication | Journal of Magnetism and Magnetic Materials | Abbreviated Journal | |
| Volume | 322 | Issue | 5 | Pages | 488-493 |
| Keywords | Manganite nanotubes; Micromachined magnetometers; Shape anisotropy | ||||
| Abstract | Using a silicon micromechanical resonator as a sensitive magnetometer, the authors have studied both experimentally and theoretically the magnetic behavior of two isolated ferromagnetic nanotubes of perovskite La0.67Ca0.33MnO3. The article investigates the specific configuration where a magnetic field H is applied perpendicular to the magnetic easy axis of an isolated nanotube characterized by an uniaxial anisotropy constant K. In this situation, the magnetization M reduces the effective elastic constant kM of the resonator. This softening of the mechanical system is opposed to the hardening effect of M observed in a previous work, where H was applied parallel to the easy axis. Moreover, in this magnetic field configuration two distinct magnetization regimes are manifested, depending on the magnitude of H. For H[not double greater-than sign]2K/M the magnetization is almost parallel to the applied magnetic field and for H[double less-than sign]2K/M it is almost parallel to the easy axis of the nanotube. At a certain value of H there is a sharp transition | ||||
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| ISSN | 0304-8853 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | BT @ hernan @ 13272 | Serial | 585 | ||
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| Author |
Betancourth, D.; Facio, J.I.; Pedrazzini, P.; Jesus, C.B.R.; Pagliuso, P.G.; Vildosola, V.; Cornaglia, P.S.; García, D. J.; Correa, V. F. | ||||
| Title | Low Temperature magnetic properties of GdCoIn5 | Type | Journal Article | ||
| Year | 2015 | Publication | Journal of Magnetism and Magnetic Materials | Abbreviated Journal | J. Magn. Magn. Mater. |
| Volume | 374 | Issue | Pages | 744-747 | |
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| Abstract | A comprehensive experimental and theoretical study of the low temperature properties of GdCoIn5 was performed. Specific heat, thermal expansion, magnetization and electrical resistivity were measured in good quality single crystals down to 4He temperatures. All the experiments show a second-order-like phase transition at 30 K probably associated with the onset of antiferromagnetic order. The magnetic susceptibility shows a pronounced anisotropy below T N with an easy magnetic axis perpendicular to the crystallographic ĉ-axis. Total energy GGA+U calculations indicate a ground state with magnetic moments localized at the Gd ions and allowed a determination of the Gd-Gd magnetic interactions. Band structure calculations of the electron and phonon contributions to the specific heat together with Quantum Monte Carlo calculations of the magnetic contributions show a very good agreement with the experimental data. Comparison between experiment and calculations suggests a significant anharmonic contribution to the specific heat at high temperature (View the MathML sourceT≳100K). | ||||
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| Notes | Approved | no | |||
| Call Number | BT @ victor.correa @ | Serial | 701 | ||
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| Author |
Braghta, A.; Schmerber, G.; Derory, A.; Sereni, J.G.; Kappler, J.P. | ||||
| Title | Magnetic and thermal properties of Ce2Pd2Sn | Type | Journal Article | ||
| Year | 2008 | Publication | Journal of Magnetism and Magnetic Materials | Abbreviated Journal | J. Magn. Magn. Mater. |
| Volume | 320 | Issue | 6 | Pages | 1141-1145 |
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| Abstract | X-ray diffraction, susceptibility and specific heat studies on ternary Ce2Pd2Sn intermetallic compound and on its isostructural nonmagnetic compound La2Pd2Sn are reported. On Ce2Pd2Sn in absence of magnetic field, we confirm the existence of two magnetic transitions at T-N = 4.8K (antiferromagnetic transition) and T-C = 2.2K (ferromagnetic transition) and the specific heat results, measured down to 0.5 K, allow to recognize the transition at 2.2K as a first-order transition. A description based on molecular field calculations for the S = 1/2 resonant level model leads to a characteristic Kondo T-K of about 3K. (C) 2007 Elsevier B.V. All rights reserved. | ||||
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| ISSN | 0304-8853 | ISBN | Medium | ||
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| Notes | ISI:000254416300060 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 49 | ||
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| Author |
Carreras Oropesa, W.G.; Encina, S.; Pedrazzini, P.; Correa, V.F.; Sereni, J.G.; Vildosola, V.; García D.J.; Cornaglia, P.S. | ||||
| Title | Minimal model for the magnetic phase diagram of CeTi1-xScxGe, GdFe1-xCoxSi, and related materials | Type | Journal Article | ||
| Year | 2020 | Publication | Journal of Magnetism and Magnetic Materials | Abbreviated Journal | |
| Volume | 503 | Issue | Pages | 166614 | |
| Keywords | Magnetism; RTX | ||||
| Abstract | We present a theoretical analysis of the magnetic phase diagram of CeTi1-xScxGe and GdFe1-xCoxSi as a function of the temperature and the Sc and Co concentration x, respectively. CeScGe and GdCoSi, as many other RTX (R=rare earth, T=transition metal, X=p-block element) compounds, present a tetragonal crystal structure where bilayers of R are separated by layers of T and X. While GdFeSi and CeTi0.75Sc0.25Ge are ferromagnetic, CeScGe and GdCoSi order antiferromagnetically with the R 4f magnetic moments on the same bilayer aligned ferromagnetically and magnetic moments in nearest neighbouring bilayers aligned antiferromagnetically. The antiferromagnetic transition temperature TN decreases with decreasing concentration x in both compounds and for low enough values of x the compounds show a ferromagnetic behavior. Based on these observations we construct a simplified model Hamiltonian that we solve numerically for the specific heat and the magnetization. We find a good qualitative agreement between the model and the experimental data. Our results show that the main magnetic effect of the Sc→Ti and Co→Fe substitution in these compounds is consistent with a change in the sign of the exchange coupling between magnetic moments in neighbouring bilayers. We expect a similar phenomenology for other magnetic RTX compounds with the same type of crystal structure. |
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| Notes | Approved | no | |||
| Call Number | BT @ victor.correa @ | Serial | 856 | ||
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| Author |
Facio, J.I.; Betancourth, D.; Cejas Bolecek, N.R.; Jorge, G.A.; Pedrazzini, P.; Correa, V.F.; Cornaglia, P.S.; Vildosola, V.; García D.J. | ||||
| Title | Lattice specific heat for the RMIn5 (R=Gd, La,Y; M=Co, Rh) compounds: Non-magnetic contribution subtraction | Type | Journal Article | ||
| Year | 2016 | Publication | Journal of Magnetism and Magnetic Materials | Abbreviated Journal | J. Magn. Magn. Mater. |
| Volume | 407 | Issue | Pages | 406-4011 | |
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| Notes | Approved | no | |||
| Call Number | BT @ victor.correa @ | Serial | 730 | ||
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| Author |
Fraga, G.L.F.; Brandao, D.E.; Sereni, J.G. | ||||
| Title | Specific heat of X2MnSn (X = Co, Ni, Pd, Cu), X2MnIn (X = Ni, Pd) and Ni2MnSb Heusler compounds | Type | Journal Article | ||
| Year | 1991 | Publication | Journal of Magnetism and Magnetic Materials | Abbreviated Journal | J. Magn. Magn. Mater. |
| Volume | 102 | Issue | 1-2 | Pages | 199-207 |
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| Abstract | Results of low-temperature specific heat measurements (1.5-8.0 K) on X2MnSn (X = Co, Ni, Pd, Cu), X2Mnln (X = Ni, Pd) and Ni2MnSb Heusler compounds are presented. All the compounds, except the cobalt based one, exibit a lattice spectrum anomaly described by an Einstein's term (soft-phonons). For all but one compound, the experimental values of the electronic specific heat coefficients are, at least, twice as big as the theoretical estimates. For two compounds it was possible to determine the magnetic effective field on Mn nuclei. | ||||
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| ISSN | 0304-8853 | ISBN | Medium | ||
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| Notes | ISI:A1991GX03900034 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 117 | ||
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| Author |
Franco, D.G.; Carbonio, R.E.; Kaul, E.E.; Nieva, G. | ||||
| Title | Tailoring the ground state of the ferrimagnet La2Ni(Ni1/3Sb2/3)O6 | Type | Journal Article | ||
| Year | 2013 | Publication | Journal of Magnetism and Magnetic Materials | Abbreviated Journal | J. Magn. Magn. Mater. |
| Volume | 346 | Issue | Pages | 196-202 | |
| Keywords | Ferrimagnetic; Double perovskite; Magnetic frustration; Superexchange and super-superexchange interaction; Magnetic oxide | ||||
| Abstract | We report on the magnetic and structural properties of La2Ni(Ni1/3Sb2/3)O6 in polycrystal, single crystal and thin film samples. We found that this material is a ferrimagnet ( T c ≈ 100 K ) which possesses a very distinctive and uncommon feature in its virgin curve of the hysteresis loops. We observe that bellow 20 K it lies outside the hysteresis cycle, and this feature was found to be an indication of a microscopically irreversible process possibly involving the interplay of competing antiferromagnetic interactions that hinder the initial movement of domain walls. This initial magnetic state is overcome by applying a temperature dependent characteristic field. Above this field, an isothermal magnetic demagnetization of the samples yield a ground state different from the initial thermally demagnetized one. | ||||
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| ISSN | 0304-8853 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | BT @ pedrazp @ | Serial | 666 | ||
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| Author |
Granada, M.; Maiorov, B.; Sirena, M.; Steren, L.B.; Guimpel, J. | ||||
| Title | Hall effect in La0.6Sr0.4MnO3 thin films | Type | Journal Article | ||
| Year | 2004 | Publication | JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS | Abbreviated Journal | |
| Volume | 272 | Issue | Pages | 1836-1838 | |
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| Abstract | We studied the temperature and thickness dependence of the transport properties of La0.6Sr0.4MnO3 films. Hall voltage and magnetoresistance measurements on 10 and 150 nm thick films were performed with this porpose. From the ordinary Hall component, we calculated the density of carriers, which has hole-character and is systematically lower than that expected from the chemical composition of the manganite in both samples. Localization effects observed at low temperature in the resistivity of the thinner film, associated with the substrate-induced disorder, are correlated with a decrease of the density of carriers. (C) 2003 Elsevier B.V. All rights reserved. | ||||
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| ISSN | 0304-8853 | ISBN | Medium | ||
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| Notes | ISI:000222236800084 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 164 | ||
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| Author |
Haberkorn, N.; Larregola, S.; Franco, D.; Nieva, G. | ||||
| Title | Inhomogeneous ferrimagnetic-like behavior in Gd2/3Ca1/3MnO3 single crystals | Type | Journal Article | ||
| Year | 2009 | Publication | JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS | Abbreviated Journal | |
| Volume | 321 | Issue | 9 | Pages | 1133-1136 |
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| Abstract | We present a study of the magnetic properties of Gd2/3Ca1/3MnO3 single crystals at low temperatures, showing that this material behaves as an inhomogeneous ferrimagnet. In addition to small saturation magnetization at 5 K, we have found history dependent effects in the magnetization and the presence of exchange bias. These features are compatible with microscopic phase separation in the clean Gd2/3Ca1/3MnO3 system studied. (C) 2008 Elsevier B.V. All rights reserved. | ||||
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| ISSN | 0304-8853 | ISBN | Medium | ||
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| Notes | ISI:000264170500007 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 194 | ||
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| Author |
Haberkorn, N.; Sirena, M.; Guimpel, J.; Steren, L.B. | ||||
| Title | Disorder influence on the magnetic properties of La0.55Sr0.45MnO3/SrTiO3 superlattices | Type | Journal Article | ||
| Year | 2004 | Publication | JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS | Abbreviated Journal | |
| Volume | 272 | Issue | Pages | 1244-1246 | |
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| Abstract | The structural and physical properties of La0.55Sr0.45MnO3/SrTiO3 superlattices grown by magnetron sputtering are studied. Two deposition temperatures and different mismatched substrates and buffer layers were used. The structure was determined by refinement through X-ray diffraction pattern fitting. The results indicate 1 unit cell (u.c.) interdiffusion at the interfaces and a 1 u.c. layer thickness fluctuation, i.e. roughness. In-plane hysteresis loops show the expected ferromagnetic behavior, while the perpendicular-to-plane hysteresis loops show anomalies which could evidence magnetic domain size inhomogeneities and stress. (C) 2004 Elsevier B.V. All rights reserved. | ||||
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| ISSN | 0304-8853 | ISBN | Medium | ||
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| Notes | ISI:000222236700212 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 163 | ||
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