Coercivity Reduction in Nickel Ferrite (NiFe&lt;formula formulatype="inline"&gt;&lt;tex Notation="TeX"&gt;$_{2}$&lt;/tex&gt;&lt;/formula&gt;O &lt;formula formulatype="inline"&gt;&lt;tex Notation="TeX"&gt;$_{4}$&lt;/tex&gt;&lt;/formula&gt;) Thin Films Through Surface Patterning

Rasic, Goran; Schwartz, J.

doi:10.1109/lmag.2014.2302246

Cited by 8 publications

(11 citation statements)

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“…All films are fully crystallized and no sign of feature damage is observed. In addition, and corresponding to previous studies , there is no indication of grain growth disruption. Looking at the feature heights, summarized in Table , we see a reduction with reduced feature size starting with the 900 nm sample.…”

Section: Resultssupporting

confidence: 88%

“…Similar to previous reports , a sol–gel solution of 0.2 M NFO was prepared by separately mixing 2.4884 g of nickel(II) acetate tetrahydrate (C 4 H 6 NiO 4 · 4H 2 O) and 8.08 g of iron(III) nitrate nonahydrate (Fe(NO 3 ) 3 · 9H 2 O) in 20 mL of 2‐methoxyethanol (CH 3 OCH 2 CH 2 OH) solvent each (all from Sigma–Aldrich). The solutions were stirred at 70 °C in ambient conditions for 2 h before being mixed together for 15 min and allowed to cool to room temperature.…”

Section: Sample Synthesis and Experimental Detailsmentioning

confidence: 99%

“…Feature sizes ranged from 500 to 1300 nm in 200 nm increments and were varied by changing the angle of the incident beam . For control, and comparison with previous work , standard compact disc (CD) and digital versatile disc (DVD) masters were also used. The CD and DVD were prepared by carefully removing the protective aluminum layers, exposing the features.…”

Section: Sample Synthesis and Experimental Detailsmentioning

confidence: 99%

“…At present, this is accomplished through doping and alloying , but a constraint on device manufacturing remains due to the limitations on material selection . Recently, however, we reported a method to reduce the coercivity in single and multilayered thin films using surface patterning. By affecting only coercivity and maintaining the saturation magnetization, texture and hysteresis curve shape, we eliminate many material selection constraints; one can design devices starting with the most suitable material and pattern the surface to minimize coercivity.…”

Section: Introductionmentioning

confidence: 99%

“…Lett. 5 , 1 (2014) ). Here, we report on the effects of varying the feature size on magnetic behavior, including loss, and explain the reduced coercivity theoretically.…”

mentioning

confidence: 99%

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On the origin of coercivity reduction in surface patterned magnetic thin films

Rasic

Schwartz

2014

Phys. Status Solidi A

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Spinel nickel ferrite (NiFe2O4) is a promising material for next generation high‐frequency sensors, antennae and microwave devices. A key issue to be addressed is the magnetic loss, which is proportional to frequency and becomes substantial at frequencies above 1 GHz. Previously, we reported on coercivity reduction in NiFe2O4 through surface patterning (Rasic and Schwartz, MRS Commun. 3, 207 (2013) and IEEE Magn. Lett. 5, 1 (2014) ). Here, we report on the effects of varying the feature size on magnetic behavior, including loss, and explain the reduced coercivity theoretically. Nickel ferrite thin films were deposited on c‐plane sapphire substrates using chemical solution deposition and patterned via nanoimprint lithography with patterning masters having feature sizes varying from 500 to 1500 nm in 200 nm increments. Atomic force microscopy showed good feature transfer for all samples. X‐ray diffraction images showed all samples to be single‐phase inverse spinel nickel ferrite with similar texture. All patterned samples showed coercivity reductions relative to the unpatterned samples. The effects of feature size on coercivity reduction showed opposite trends for in‐plane and out‐of‐plane magnetization hysteresis measurements, whereas saturation magnetization was not affected by feature size changes. Magnetic force microscopy images confirmed the origin of coercivity reduction to be shape‐anisotropy‐forced alternating domain formation. The coercivity reduction phenomena observed in patterned NiFe2O4 thin films are explained theoretically. The effect of changing the film thickness and domain size on the equilibrium energy density was calculated. While the relative energy density showed a stable equilibrium, the energy increase for domain sizes equaling that of patterned films in this study was small. Finally, the new domain structure in patterned NiFe2O4 films was explained within micromagnetism theory.

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Section: Resultssupporting

confidence: 88%

Section: Sample Synthesis and Experimental Detailsmentioning

confidence: 99%

Section: Sample Synthesis and Experimental Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Lett. 5 , 1 (2014) ). Here, we report on the effects of varying the feature size on magnetic behavior, including loss, and explain the reduced coercivity theoretically.…”

mentioning

confidence: 99%

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