Temperature dependent coercivity and magnetization of nickel ferrite nanoparticles

Maaz, K.; Mumtaz, Arif; Hasanain, S. K.; Bertino, Massimo F.

doi:10.1016/j.jmmm.2010.02.010

Cited by 181 publications

(89 citation statements)

References 24 publications

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“…The temperature dependence of the saturation magnetization, M S in bulk ferromagnetic or ferrimagnetic materials at low temperatures is governed by the Bloch's law [39][40][41][42].…”

Section: Magnetic Propertiesmentioning

confidence: 99%

“…The exponent α B is known as the Bloch's exponent (α B ) and the value of α B is 3/2 for bulk materials. Bloch proposed the T 3/2 law by considering the magnon excitation of long wave-length spin-waves at low temperatures [39]. Figure 6 shows the temperature dependence of M S measured under the ZFC protocol for all the samples.…”

Section: Magnetic Propertiesmentioning

confidence: 99%

“…Various suggestions were made to explain the deviation from the Bloch's law in nanoparticle systems [49,[56][57][58][59][60][61][62]. For nickel ferrite nanoparticles, the modified Bloch's model was found to be valid for temperatures between 50 and 300 K [39]. At temperatures lower than 50 K, the authors reported a deviation from the modified Bloch law where a sharp increase in saturation magnetization occurred [39].…”

Section: Hfc (T)mentioning

confidence: 99%

“…For nickel ferrite nanoparticles, the modified Bloch's model was found to be valid for temperatures between 50 and 300 K [39]. At temperatures lower than 50 K, the authors reported a deviation from the modified Bloch law where a sharp increase in saturation magnetization occurred [39]. This anomaly was suggested to be due to some extra contribution of the shell-spins moment to the total magnetization at low temperatures [39,60] or due to the presence of some paramagnetic impurities in the nanoparticles which would be activated at low temperatures [39,61].…”

Section: Hfc (T)mentioning

confidence: 99%

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Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

2017

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Abstract:Understanding saturation magnetization and its behavior with particle size and temperature are essential for medical applications such magnetic hyperthermia. We report the effect of shell thickness and field cooling on the saturation magnetization and its behavior with temperature in Fe 3 O 4 /γ-Fe 2 O 3 core/shell nanoparticles of fixed core diameter (8 nm) and several shell thicknesses. X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM, high-resolution transmission electron microscopy (HRTEM)) were used to investigate the phase and the morphology of the samples. Selected area electron diffraction (SAED) confirmed the core/shell structure and phases. Using a SQUID (San Diego, CA, USA), magnetic measurements were conducted in the temperature range of 2 to 300 K both under zero field-cooling (ZFC) and field-cooling (FC) protocols at several field-cooling values. In the ZFC state, considerable enhancement of saturation magnetization was obtained with the increase of shell thickness. After field cooling, we observed a drastic enhancement of the saturation magnetization in one sample up to 120 emu/g (50% larger than the bulk value). In both the FC and ZFC states, considerable deviations from the original Bloch's law were observed. These results are discussed and attributed to the existence of interface spin-glass clusters which are modified by the changes in the shell thickness and the field-cooling.

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“…The temperature dependence of the saturation magnetization, M S in bulk ferromagnetic or ferrimagnetic materials at low temperatures is governed by the Bloch's law [39][40][41][42].…”

Section: Magnetic Propertiesmentioning

confidence: 99%

Section: Magnetic Propertiesmentioning

confidence: 99%

Section: Hfc (T)mentioning

confidence: 99%

Section: Hfc (T)mentioning

confidence: 99%

See 2 more Smart Citations

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

2017

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“…Ранее было установлено, что закон Кнеллера применим к самым различным наночастицам: Fe [7], Cu [15] и др. При этом в работах [9,12,14] были обнаружены расхождения между экспериментальными зависимостя-ми H C (T ) и формулой Кнеллера, которые объясня-ются несколькими факторами: в первую очередь -распределением наночастиц по размерам. Также -диполь-дипольным взаимодействием между наночасти-цами, неупорядоченностью поверхностных спинов, ко-торые влияют на поверхностную анизотропию и, сле-довательно, суммарную анизотропию наночастиц, раз-бросом осей легкого намагничивания и т. д. Как видно из рис.…”

Section: результаты и обсуждениеunclassified

Общность процессов спонтанного и вынужденного перемагничивания кластеров MnSb, внедренных в тонкие пленки GaMnSb

Дмитриев¹,

Филатов²

2017

Физика Твердого Тела

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Обнаружена общность процессов спонтанного и вынужденного перемагничивания кластеров MnSb, внедренных в тонкие пленки GaMnSb. Родство термоактивационных и полевых процессов перемагничивания экспериментально выражается в том, что максимум на полевых зависимостях магнитной вязкости S(H) совпадает с коэрцитивной силой HC образца. Анализ этого экспериментального факта позволил получить формулу, устанавливающую связь HC с параметрами модели, описывающей зависимости S(H). Полученная формула идентична известному закону Кнеллера, определяющему температурную зависимость HC (T ) невзаимодействующих суперпарамагнитных наночастиц.Работа поддержана грантом Президента РФ МК-5754.2016.3.

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Chiral Spin Textures in Amorphous Iron–Germanium Thick Films

et al. 2021

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Topological solitary fields, such as magnetic and polar skyrmions, are envisioned to revolutionize microelectronics. These configurations have been stabilized in solid-state materials with a global inversion symmetry breaking, which translates in magnetic materials into a vector spin exchange known as the Dzyaloshinskii-Moriya interaction (DMI), as well as spin chirality selection and isotropic solitons. This work reports experimental evidence of 3D chiral spin textures, such as helical spins and skyrmions with different chirality and topological charge, stabilized in amorphous Fe-Ge thick films. These results demonstrate that structurally and chemically disordered materials with a random DMI can resemble inversion symmetry broken systems with similar magnetic properties, moments, and states. Disordered systems are distinguished from systems with global inversion symmetry breaking by their degenerate spin chirality that allows for forming isotropic and anisotropic topological spin textures at remanence, while offering greater flexibility in materials synthesis, voltage, and strain manipulation. The discovery of unprecedented physical properties and application potential of topologically protected non-collinear states in condensed matter has greatly influenced the direction of

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Temperature dependent coercivity and magnetization of nickel ferrite nanoparticles

Cited by 181 publications

References 24 publications

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

Общность процессов спонтанного и вынужденного перемагничивания кластеров MnSb, внедренных в тонкие пленки GaMnSb

Chiral Spin Textures in Amorphous Iron–Germanium Thick Films

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