Manganese-substituted cobalt ferrite magnetostrictive materials for magnetic stress sensor applications

Self Cite

Threading dislocation-governed degradation in crystal quality of heteroepitaxial materials: The case of InAlN nearly lattice-matched to GaN J. Appl. Phys. 111, 053535 (2012) Ferroelectric domain structures of 0.4-μm-thick Pb(Zr,Ti)O3 films prepared by polyvinylpyrrolidone-assisted SolGel method J. Appl. Phys. 111, 054109 (2012) Columnar grain growth of FePt (L10) Cobalt ferrite thin films were grown on SiO 2 / Si͑100͒ substrates using pulsed-laser deposition technique at substrate temperatures ranging from 250 to 600°C. Thermal expansion mismatch between the film and substrate appears to have a substantial effect on the magnetic properties of the cobalt ferrite films, due to the large magnetoelastic coupling of cobalt ferrite. It was shown in this study, that polycrystalline films with ͑111͒-preferred orientation could be prepared at substrate temperatures as low as 250°C. The growth of crystalline cobalt ferrite films at such low temperatures indicates the potential to use cobalt ferrite for microelectromechanical systems devices and sensor applications including integration with a wider range of multilayer device structures.

Section: Introductionmentioning

confidence: 99%

“…5 Depending on the requirements of application, magnetic and magnetoelastic properties of CFO can be fine-tuned by appropriate cation substitution 1,[6][7][8] and magnetic annealing. 9 The optimum substrate temperature for thin film growth has been reported to be 600°C, 10 in order to produce crystalline CFO.…”

Section: Introductionmentioning

confidence: 99%

Growth of crystalline cobalt ferrite thin films at lower temperatures using pulsed-laser deposition technique

Raghunathan

Nlebedim

Jiles

et al. 2010

Self Cite

“…1,2 Substitution of elements such as Mn or Cr for some of the Fe has shown promise of adjusting the magnetic and magnetoelastic properties of these materials through control of chemical composition. 3,4 In order to fully enable the practical applications of these compounds, a more complete family of materials is needed, such that the desired properties can be tailored to a specific application. In the present study, we report on the magnetic characterization of the series of Ga-substituted cobalt ferrites CoGa x Fe 2−x O 4 ͑x = 0.0-0.8͒ as a function of gallium concentration using transmission Mossbauer spectroscopy.…”

mentioning

confidence: 99%

Investigation of Ga substitution in cobalt ferrite (CoGaxFe2−xO4) using Mossbauer spectroscopy

Krieble¹,

Devlin²,

Lee³

et al. 2008

Self Cite

Ga-substituted cobalt ferrite oxides show promise as high magnetostriction, high sensitivity magnetoelastic materials for sensor and actuator applications, but their atomic-level behavior is not yet well understood. In this study, the magnetic environments of the Fe atoms in Ga-substituted cobalt ferrite have been investigated using Mossbauer spectroscopy. A series of five powder samples with CoGa x Fe 2−x O 4 compositions ͑x = 0.0-0.8͒ was investigated using transmission geometry. Results show two distinct six-line hyperfine patterns, which are identified as Fe in A ͑tetrahedral͒ and B ͑octahedral͒ spinel sites. Increasing Ga concentration is seen to decrease the hyperfine field strength for both A and B sites, as well as increasing the width of those distributions, consistent with the nonmagnetic nature of Ga 3+ ions. Effects are more pronounced for the B sites than the A sites. Results for Ga substitution show more pronounced effects than for previous studies with Cr 3+ or Mn 3+ substitution: the hyperfine fields decrease and distribution widths increase at greater rates, and the differences between A and B site behavior are more pronounced. Results indicate that at least for the lower Ga concentrations, the Ga 3+ ions substitute predominantly into the A sites, in contrast to Cr 3+ and Mn 3+ which substitute into the B sites. This interpretation is supported by measurements of magnetization at low temperatures. © 2008 American Institute of Physics. ͓DOI: 10.1063/1.2834721͔ INTRODUCTIONThe development of cobalt ferrite-based materials has received recent attention for the potential applicability of such materials as magnetoelastic sensors and actuators, and as the magnetoelastic component in composite "multiferroics." 1,2 Substitution of elements such as Mn or Cr for some of the Fe has shown promise of adjusting the magnetic and magnetoelastic properties of these materials through control of chemical composition. 3,4 In order to fully enable the practical applications of these compounds, a more complete family of materials is needed, such that the desired properties can be tailored to a specific application. In the present study, we report on the magnetic characterization of the series of Ga-substituted cobalt ferrites CoGa x Fe 2−x O 4 ͑x = 0.0-0.8͒ as a function of gallium concentration using transmission Mossbauer spectroscopy. The effects of this substitution were expected to be different for Mn and Cr substitution. [5][6][7] EXPERIMENTAL DETAILSThe samples used in this study were prepared at Ames Laboratory, USDOE. The samples were of the composition CoGa x Fe 2−x O 4 ͑where x = 0.0-0.8͒. Standard powder ceramic techniques were employed using Fe 2 O 3 , Ga 2 O 3 , and Co 3 O 4 powders as precursors. The powders were calcined twice, sintered at 1350°C for 24 h, and furnace cooled ͑see Ref. 7 for details͒. The final compositions of the samples were determined by energy-dispersive x-ray spectroscopy, and all samples were confirmed by x-ray powder diffractometry to be single phase and have the cubic spinel ...

“…The magnetic properties or magneto-optic properties, including the exchange interactions, of these ferrites have been found to be dependent on how the cations are distributed among the two sublattices. [6][7][8] Recently, cobalt ferrite composites 9 and their Mnsubstituted modifications 10 have been actively investigated as part of the development of materials for highly sensitive noncontact stress and torque sensors. It was observed that the substitution of Mn for Fe led to the reduction of both the Curie temperature and the magnetostriction with increasing Mn content.…”

Section: Introductionmentioning

confidence: 99%

Magneto-optic properties of CoFe2−xGaxO4

Lee

Song

et al. 2007

Self Cite

Long-lived, room-temperature electron spin coherence in colloidal CdS quantum dots Appl. Phys. Lett. 100, 122406 (2012) Resonant surface magnetoplasmons in two-dimensional magnetoplasmonic crystals excited in Faraday configuration J. Appl. Phys. 111, 07A946 (2012) Research on cobalt ferrite based composites has increased recently due to their potential applications such as noncontact magnetoelastic stress or torque sensors and erasable magneto-optic recording media. We report a study of the polar Kerr rotation spectra for CoFe 2−x Ga x O 4 ͑with x = 0.4 and x = 0.8͒. Each of the spectra consists of two peaks of negative Kerr rotation in the measured photon energy range of 1.5-3.0 eV. For x = 0.4, one peak occured at 1.8 eV and the other at 2.25 eV. For x = 0.8, the first peak shifted to a higher energy of about 1.9 eV, while the second peak remained at 2.25 eV. The origin of the peaks in the polar Kerr spectra and the observed shift of peak position resulting from Ga substitution can be explained by the intervalence charge-transfer transition, in which an electron from a metallic cation is transferred to a neighboring cation through an optical excitation.