Magnetic field melting of the charge-ordered state of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>La</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>∕</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>Ca</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>∕</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>MnO</mml:mtext></mml:mrow><mml:mn>3</mml:mn></mml:msub></mm

Tyson, Trevor; Deleon, M.; Croft, Mark; Harris, Vincent G.; Kao, Chi Chang; Kirkland, J. P.; Cheong, Sang‐Wook

doi:10.1103/physrevb.70.024410

Cited by 14 publications

(13 citation statements)

References 56 publications

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“…Similar, field induced changes in the Mn-Mn distribution were also found in high magnetic field XAFS measurements of the melting of the charge/orbitally ordered ͑C-O͒ state of La 0.5 Ca 0.5 MnO 3 . 63 Examination of the Mn-O and Mn-Mn correlations revealed three distinct regions in the structure-field diagram: a broad region with weak field dependence ͑C-O region, disordered͒, a mixed phase region, and a high field ͑above 9 T͒ ferromagnetic phase with low disorder and strong magnetic fieldstructure coupling.…”

Section: Experimental Standards and Further Neighbor Fitsmentioning

confidence: 99%

Detailed relationship between local structure, polarons, and magnetization forLa1−xCaxMnO3
Bridges
¹
,
Downward
²
,
Neumeier
³

et al. 2010
Phys. Rev. B
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We present detailed local structure measurements ͑using the extended x-ray absorption fine structure tech-nique͒ for the colossal magnetoresistive material La 1−x Ca x MnO 3 ͑0.21Ͻ x Ͻ 0.45͒ as a function of temperature and magnetic field. The local distortions of the Mn-O bonds are parameterized using , the width of the Mn-O pair-distribution function ͑PDF͒. After subtracting thermal phonon contributions, we show that the contributions to 2 from polaron and Jahn-Teller ͑JT͒ distortions, JT/polaron 2 , are a universal function of the magnetization, independent of how the magnetization is achieved via changes in temperature or magnetic field. However this universal behavior is only observed for B fieldsՆ 2 T, likely as a result of domain canting in low B fields. The resulting curve is well described by two straight lines with significantly different slopes. These regimes represent two distinctly differ distortions of the oxygen octahedra about the Mn. For low magnetizations up to ϳ65% of the theoretical maximum magnetization, M T , the slope is low and the distortion removed as the sample becomes magnetized is small-we argue this arises from polarons which have a low distortion around two ͑or possibly three͒ Mn sites. At high magnetizations large distortions per Mn site are removed as these sites become magnetized. The data are also analyzed in terms of a two Mn-O peak distribution using experimental standards for Mn-O. The results agree well with recent neutron PDF results but not with some earlier results. We discuss the limitations of assuming a two peak distribution in view of the two distortions needed to describe the Mn-O distortions as a function of T and B for B Ն 2 T. It is likely that there is a distribution of longer bonds. Finally we show that with increasing B field, the Mn-Mn peak also has a small B-field-induced change-a measure at the unit cell level of magnetostriction but find that there is no observable B-field-induced change in the Mn-La/Ca pair distribution for fields up to ϳ10 T.

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Section: Experimental Standards and Further Neighbor Fitsmentioning

confidence: 99%

Detailed relationship between local structure, polarons, and magnetization forLa1−xCaxMnO3
Bridges
¹
,
Downward
²
,
Neumeier
³

et al. 2010
Phys. Rev. B
Self Cite
27
4
20
1
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show abstract

“…While some of the reports concentrate on determining the magnetic and crystalline aspects of the structure at different temperatures [13], some deal with the local structure and importance of the Mn-O bond lengths [26]. Magnetic field-induced melting of the charge ordered state [27] and phase coexistence of antiferromagnetic and ferromagnetic states due to supercooling [28] have also been discussed. In the present neutron diffraction measurements, we show that the FOPT from high temperature ferromagnetic state to a low temperature antiferromagnetic state is completely or partially arrested (depending on the path taken during cooling in a magnetic field) due to hindered kinetics, resulting in glass-like arrested states or GLAS.…”

Section: Neutron Diffractionmentioning

confidence: 99%

Neutron diffraction evidence for kinetic arrest of first order magneto-structural phase transitions in some functional magnetic materials

Siruguri

Babu

Kaushik

et al. 2013

J. Phys.: Condens. Matter

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Neutron diffraction measurements, performed in the presence of an external magnetic field, have been used to show structural evidence for the kinetic arrest of the first order phase transition from (i) the high temperature austenite phase to the low temperature martensite phase in the magnetic shape memory alloy Ni37Co11Mn42.5Sn9.5, (ii) the higher temperature ferromagnetic phase to the lower temperature antiferromagnetic phase in the half-doped charge ordered compound La0.5Ca0.5MnO3 and (iii) the formation of glass-like arrested states in both compounds. The cooling and heating under unequal fields protocol has been used to establish phase coexistence of metastable and equilibrium states, and also to demonstrate the devitrification of the arrested metastable states in the neutron diffraction patterns. We also explore the field–temperature dependent kinetic arrest line TK(H), through the transformation of the arrested phase to the equilibrium phase. This transformation has been observed isothermally in reducing H, as also on warming in constant H. TK is seen to increase as H increases in both cases, consistent with the low-T equilibrium phase having lower magnetization.

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“…This is consistent with x-ray measurements in La 1/2 Ca 1/2 MnO 3 in a field. 38,39 Starting from the distorted CE phase, we find in addition an instability of the high-field ferromagnetic phase to the formation of JT defects. This suggests that the high-field phase seen in experiments may need a two-fluid description.…”

mentioning

confidence: 90%

Instabilities and insulator-metal transitions in half-doped manganites induced by magnetic-field and doping

2006

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We discuss the phase diagram of the two-orbital model of half-doped manganites by calculating self-consistently the Jahn-Teller (JT) distortion patterns, charge, orbital and magnetic order at zero temperature. We analyse the instabilities of these phases caused by electron or hole doping away from half-doping, or by the application of a magnetic-field. For the CE insulating phase of halfdoped manganites, in the intermediate JT coupling regime, we show that there is a competition between canting of spins (which promotes mobile carriers) and polaronic self-trapping of carriers by JT defects. This results in a marked particle-hole asymmetry, with canting winning only on the electron doped side of half-doping. We also show that the CE phase undergoes a first-order transition to a ferromagnetic metallic phase when a magnetic-field is applied, with abrupt changes in the lattice distortion patterns. We discuss the factors that govern the intriguingly small scale of the transition fields. We argue that the ferromagnetic metallic phases involved have two types of charge carriers, localised and band-like, leading to an effective two-fluid model.

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Magnetic field melting of the charge-ordered state ofLa1∕2Ca1∕2MnO3

Cited by 14 publications

References 56 publications

Detailed relationship between local structure, polarons, and magnetization forLa1−xCaxMnO3
Bridges
¹
,
Downward
²
,
Neumeier
³

et al. 2010
Phys. Rev. B
Self Cite
27
4
20
1
View full text Add to dashboard Cite

Detailed relationship between local structure, polarons, and magnetization forLa1−xCaxMnO3
Bridges
¹
,
Downward
²
,
Neumeier
³

et al. 2010
Phys. Rev. B
Self Cite
27
4
20
1
View full text Add to dashboard Cite

Neutron diffraction evidence for kinetic arrest of first order magneto-structural phase transitions in some functional magnetic materials

Instabilities and insulator-metal transitions in half-doped manganites induced by magnetic-field and doping

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Magnetic field melting of the charge-ordered state ofLa1∕2Ca1∕2MnO3

Cited by 14 publications

References 56 publications

Detailed relationship between local structure, polarons, and magnetization forLa1−xCaxMnO3Bridges1, Downward2, Neumeier3 et al. 2010Phys. Rev. BSelf Cite274201View full textAdd to dashboardCite

Detailed relationship between local structure, polarons, and magnetization forLa1−xCaxMnO3Bridges1, Downward2, Neumeier3 et al. 2010Phys. Rev. BSelf Cite274201View full textAdd to dashboardCite

Neutron diffraction evidence for kinetic arrest of first order magneto-structural phase transitions in some functional magnetic materials

Instabilities and insulator-metal transitions in half-doped manganites induced by magnetic-field and doping

Contact Info

Product

Resources

About

Detailed relationship between local structure, polarons, and magnetization forLa1−xCaxMnO3
Bridges
¹
,
Downward
²
,
Neumeier
³

et al. 2010
Phys. Rev. B
Self Cite
27
4
20
1
View full text Add to dashboard Cite

Detailed relationship between local structure, polarons, and magnetization forLa1−xCaxMnO3
Bridges
¹
,
Downward
²
,
Neumeier
³

et al. 2010
Phys. Rev. B
Self Cite
27
4
20
1
View full text Add to dashboard Cite