Abstract:One-dimensional CoFe2O4 microtubes have been prepared via a simple template-assembled sol-gel method. Influence of calcination temperature on structural and magnetic properties, heat capacity and specific heating rate under radiofrequency field 295 kHz was studied. A CoFe2O4 spinel was the main phase in all samples. As the calcination temperature increased, the average crystal size increased from 34.1 to 168 nm and the specific surface area decreased from 85.7 to 8.5 m 2 g -1 . When calcined at 1073 K, porous microtubes with a narrow size distribution in the range between 2.0 and 2.5 m and a length to diameter ratio exceeding 20 were obtained. The heat capacity of the microtubes calcined at 973 K was 140.81 J·mol -1 ·K -1 at 395K, being close to the theoretic value. The sample calcined at 973 K showed highest rate of 0.293 K s -1 ·mg -1 .

xia. (2015) Effect of Pr3+ substitution on the microstructure, specific surface area, magnetic properties and specific heating rate of Ni0.5Zn0.5PrxFe2−xO4 nanoparticles synthesized via sol-gel method. Journal of Alloys and Compounds,. Permanent WRAP URL:http://wrap.warwick.ac.uk/94091 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. Abstract: A series of Ni-Zn ferrite nanoparticles with a nominal composition of Ni0.5Zn0.5Prx Fe2-xO4 (x=0.000 -0.100 with steps of 0.025) has been synthesized by a sol-gel method. The effect of composition and calcination temperature on the morphology, specific surface area, magnetic properties and specific heating rate has been studied. The Ni-Zn-Pr ferrites have a single spinel (NZF) phase at Pr loadings below 5 at%. A minor amount of an orthorhombic PrFeO3 phase is present in the Ni-Zn-Pr ferrites at Pr loadings above 5 at%. At a Pr loading of 10 at%, the specific surface area increases six-fold as compared to that of the non-doped Ni0.5Zn0.5Fe2O4 sample. As the Pr loading increases, the saturation magnetization, remnant magnetization and coercivity increase and reach the maximum at x = 0.05 and then decrease. The maximum values of these parameters are 67.0 emu/g, 9.7 emu/g and 87.2Oe, respectively. Under radiofrequency field (frequency: 295 kHz, intensity: 500 Oe), the highest heating rate of 1.65 K/s was observed over the sample with x = 0.025 which is 2.5 times higher than that of Ni0.5Zn0.5Fe2O4.

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