Overcoming inherent magnetic instability, preventing spin canting and magnetic coding in an assembly of ferrimagnetic nanoparticles

Abstract

The authors find that for mechanically milled Ni0.5Zn0.5Fe2O4 (∼10 nm), the mechanical strain induced enhancement of anisotropy energy helps to retain stable magnetic order. The reduction of magnetization can be prevented by keeping the cation distribution of nanometric ferrites at its equilibrium ratio. Moreover, the sample can be used in coding, storing, and retrieving of binary bit (“0” and “1”) through magnetic field change.

Stable room temperature magnetic ordering and excellent catalytic activity of mechanically activated high surface area nanosized Ni0.45Zn0.55Fe2O4

“…[1][2][3][4][5][6][7][8][9] The unique physical properties of nanometric ferrites have been the focus of extensive research in recent years. [1][2][3][4][5][6][7][8][9] The unique physical properties of nanometric ferrites have been the focus of extensive research in recent years.…”

“…[1][2][3][4][5][6][7][8][9] The unique physical properties of nanometric ferrites have been the focus of extensive research in recent years. 9 The interest in the study on magnetic properties of nanostructured ferrites is fueled by their applications in high density data storage devices, magnetic resonance imaging (as contrast agent), magnetically guided drug delivery, hyperthermia treatment. 9 They are also regarded as an exemplary model system for understanding the underlying mechanism of superparamagnetism, spin glass like behavior, spin canting effect and ferrimagnetism.…”

“…9 They are also regarded as an exemplary model system for understanding the underlying mechanism of superparamagnetism, spin glass like behavior, spin canting effect and ferrimagnetism. 9 In recent times, the mechanically activated ferrites have come out as the potential candidates in the perspective of overcoming the direct clash between need for miniaturization and inherent superparamagnetic character of magnetic nanoparticles. 9-15 However, with decreasing particle size the magnetic anisotropy energy liable to clutch the magnetization along certain orientation becomes comparable to the thermal energy and due to this the magnetic moment ips randomly with time.…”

“…9 The interest in the study on magnetic properties of nanostructured ferrites is fueled by their applications in high density data storage devices, magnetic resonance imaging (as contrast agent), magnetically guided drug delivery, hyperthermia treatment. 3,9 It is noteworthy that the stress anisotropy induced by ball milling acts as an extra source of anisotropy energy and it helps in retaining the stable magnetic order of the nanosized Ni-Zn ferrite at room temperature. When this happens, particles lose their magnetic order and become superparamagnetic.…”

“…9-15 However, with decreasing particle size the magnetic anisotropy energy liable to clutch the magnetization along certain orientation becomes comparable to the thermal energy and due to this the magnetic moment ips randomly with time. 9 A lot of investigations have been performed on nanometric Ni x Zn 1Àx Fe 2 O 4 ferrites because of their high saturation magnetization, chemical stability and bio degradability. 9,16 The stability of magnetic order can be accomplished by the enhancement of the anisotropy energy.…”