<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mprescripts /><mml:mrow /><mml:mrow><mml:mn>139</mml:mn></mml:mrow><mml:mrow /><mml:mrow /></mml:mmultiscripts></mml:mrow></mml:math>NMR investigation of spin ordering in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn

Papavassiliou, George C.; Fardis, M.; Milia, F.; Simopoulos, A.; Kallias, G.; Pissas, M.; Niarchos, D.; Ioannidis, Nikolaos; Dimitropoulos, C.; Dolinšek, J.

doi:10.1103/physrevb.55.15000

Cited by 39 publications

(27 citation statements)

References 22 publications

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“…Preivous studies by 139 La NMR and ESR in La0.5Ca0.5MnO3 suggested the coexistence of FM/AF phases between TN and TC. 20 So, our results provide the first experimental evidence of the PM nature of the incommensurate CO phase in La0.5Ca0.5MnO3. The value of Hr ∼3150 Oe for the HF line indicates a small internal field from the FM regions acting on the CO-PM phase.…”

mentioning

confidence: 60%

Coexistence of paramagnetic-charge-ordered and ferromagnetic-metallic phases in La0.5Ca0.5MnO3 evidenced by electron spin resonance

Rivadulla

Freita-Alvite

López‐Quintela

et al. 2002

Journal of Applied Physics

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Abstract. Throughout a complete Electron Spin Resonance (ESR) and magnetization study of La0.5Ca0.5MnO3, we discuss about the nature of the complex phase-segregated state established in this compound below T∼210 K. Between TN≤T≤TC, the ESR spectra shows two lines characteristic of two different magnetic phases. From the resonance field (Hr) derived for each line we argue that the incommensurate-charge-ordering phase (ICO) which coexists with ferromagnetic-metallic (FMM) clusters in this temperature interval, is mainly paramagnetic and not antiferromagnetic. The FMM/ICO ratio can be tuned with a relatively small field, which suggests that the internal energy associated with those phases is very similar. Below TN, there is an appreciable FM contribution to the magnetization and the ESR spectra indicates the presence of FM clusters in an antiferromagnetic matrix (canted). Our results show that ESR could be a very useful tool to investigate the nature of the phase-separated state now believed to play a fundamental role in the physics of mixed valent manganites.

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confidence: 60%

Coexistence of paramagnetic-charge-ordered and ferromagnetic-metallic phases in La0.5Ca0.5MnO3 evidenced by electron spin resonance

Rivadulla

Freita-Alvite

López‐Quintela

et al. 2002

Journal of Applied Physics

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“…The phase separation phenomenon is one of them. The coexistence of different magnetic phases [5][6][7][8][9] and electrical phases 10,11 has been observed in several R 1Ϫx A x MnO 3 bulk materials, often as the occurrence of CMR phenomena. The control of phase separation by temperature and doping levels would be an important parameter to govern the material properties.…”

Section: Introductionmentioning

confidence: 98%

Effect ofA-site cation ordering on the magnetoelectric properties in[(LaMnO3)m/(
Koida
¹
,
Lippmaa
²
,
Fukumura
³

et al. 2002
Phys. Rev. B
114
4
93
0
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In order to evaluate the effect of charge transfer and/or charge ordering in La 1Ϫx Sr x MnO 3 on the magnetic and transport properties, a library of ͓(LaMnO 3 ) m /(SrMnO 3 ) m ͔ n superlattices have been fabricated by the combinatorial pulsed laser deposition method. The properties of superlattices were found to depend strongly on the periodicity m; superlattices of mр4 behaved like a solid solution La 0.5 Sr 0.5 MnO 3 film, while the superlattices of mϾ4 were significantly different from the solid solution. These superlattices exhibited a higher resistivity and lower Curie temperature than mр4 superlattices. The results indicate that the properties of the superlattices are dominated not only by the magnetic interaction between the superlattice constituents but also by carrier (e g electrons͒ transfer thorough the superlattice interface. The contribution of carrier transfer is supported by the magnetoelectric properties of another library of ͓(La 0.8 Sr 0.2 MnO 3 ) 8 /(La 0.2 Sr 0.8 MnO 3 ) m ͔ 12 superlattices. The A-site cation order can change both effective carrier concentration and magnetic interaction.

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“…In a recent paper 1 we have shown that at low temperatures the 55 Mn NMR spectra of La 0.67 Ca 0.33 MnO 3 , obtained with a two-pulse spin-echo technique, are doubly peaked with peaks at frequencies 380 MHz and 395 MHz. This effect has been attributed to the lower charge carrier density in domain walls in comparison to the charge carrier density in ferromagnetic ͑FM͒ domains.…”

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confidence: 98%

Reply to “Comment on ‘NMR in manganese perovskites: Detection of spatially varying electron states in domain walls’ ”

et al. 2001

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In their Comment Savosta and Novák claim that the doubly peaked 55 Mn NMR line shape observed in La 0.67 Ca 0.33 MnO 3 for TϽ70 K ͓Phys. Rev. B 58, 12 237 ͑1998͔͒ is not real, but an artifact resulting from the experimental conditions. In support to their arguments, they present 55 Mn line-shape measurements at 77 K. In this reply we present 55 Mn NMR line-shape measurements under the experimental requirements suggested by Savosta and Novák, and show that at low temperatures the line shape still consists of two distinct peaks with different rf enhancement factors. This effect is explained in view of recent experimental results.In a recent paper 1 we have shown that at low temperatures the 55 Mn NMR spectra of La 0.67 Ca 0.33 MnO 3 , obtained with a two-pulse spin-echo technique, are doubly peaked with peaks at frequencies 380 MHz and 395 MHz. This effect has been attributed to the lower charge carrier density in domain walls in comparison to the charge carrier density in ferromagnetic ͑FM͒ domains. For TϾ70 K, the double peak was no more observed, and spectra were found to consist of a broad single peaked Gaussian line shape.In their Comment, Savosta and Novák claim that the double peak is due to the short spin-spin relaxation time T 2 value at the center of the line shape, which distorts the central part of the signal. They claim that by using very short interpulse time intervals , such that ӶT 2 , the double peak will disappear and the true single Gaussian line shape will be restored.In order to clarify the question raised by them we performed low-temperature 55 Mn NMR line-shape measurements on La 0.67 Ca 0.33 MnO 3 , after setting ϭ3 sec, which in all measurements fulfilled the condition ӶT 2 . Figure 1͑a͒ exhibits line-shape measurements at Tϭ3.2 K, and at four different radio frequency ͑rf͒ power levels. It is clearly observed that by decreasing rf power the low-frequency part of the signal decreases rapidly, whereas the high-frequency part remains almost unchanged. This unambiguously shows that the signal consists of two components, which respond differently to the power level of the rf excitation pulse, i.e., they have different rf enhancement factor. 3 On the contrary, at 77 K ͓Fig. 1͑b͔͒ the line shape remains unchanged and only the signal intensity reduces drastically by decreasing rf power level, which implies a uniform rf enhancement across the whole spectum. The possibility that at Tϭ3.2 K the doubly peaked line shape is produced by an extremely short T 2 FIG. 1. ͑a͒ 55 Mn NMR line-shape measurements of La 0.67 Ca 0.33 MnO 3 at 3.2 K, and different rf power levels. ͑b͒ The same experiment at 77 K. FIG. 2. 55 Mn T 2 as a function of temperature measured at rf power level Ϫ5 dB ͑filled circles͒. For reasons of comparison T 2 from Ref. 1 ͑gray circles͒ is also presented.

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La139NMR investigation of spin ordering inLa

Cited by 39 publications

References 22 publications

Coexistence of paramagnetic-charge-ordered and ferromagnetic-metallic phases in La0.5Ca0.5MnO3 evidenced by electron spin resonance

Coexistence of paramagnetic-charge-ordered and ferromagnetic-metallic phases in La0.5Ca0.5MnO3 evidenced by electron spin resonance

Effect ofA-site cation ordering on the magnetoelectric properties in[(LaMnO3)m/(
Koida
¹
,
Lippmaa
²
,
Fukumura
³

et al. 2002
Phys. Rev. B
114
4
93
0
View full text Add to dashboard Cite

Reply to “Comment on ‘NMR in manganese perovskites: Detection of spatially varying electron states in domain walls’ ”

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La139NMR investigation of spin ordering inLa

Cited by 39 publications

References 22 publications

Coexistence of paramagnetic-charge-ordered and ferromagnetic-metallic phases in La0.5Ca0.5MnO3 evidenced by electron spin resonance

Coexistence of paramagnetic-charge-ordered and ferromagnetic-metallic phases in La0.5Ca0.5MnO3 evidenced by electron spin resonance

Effect ofA-site cation ordering on the magnetoelectric properties in[(LaMnO3)m/(Koida1, Lippmaa2, Fukumura3 et al. 2002Phys. Rev. B1144930View full textAdd to dashboardCite

Reply to “Comment on ‘NMR in manganese perovskites: Detection of spatially varying electron states in domain walls’ ”

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Effect ofA-site cation ordering on the magnetoelectric properties in[(LaMnO3)m/(
Koida
¹
,
Lippmaa
²
,
Fukumura
³

et al. 2002
Phys. Rev. B
114
4
93
0
View full text Add to dashboard Cite