Enhanced magnetic anisotropy of Nickel nanosheet prepared in Na-4 mica

TL;DR

This paper reports the synthesis of ultra-thin nickel nanosheets within Na-4 mica, exhibiting significantly enhanced magnetic anisotropy and superparamagnetic behavior, with size effects influencing magnetic properties.

Contribution

It introduces a novel method to produce nickel nanosheets with high magnetic anisotropy, highlighting the impact of nanoscale dimensions on magnetic properties.

Findings

Magnetic anisotropy constant is two orders of magnitude higher than bulk nickel.

Nanosheets show superparamagnetic behavior with a blocking temperature of 428 K.

Size effects alter the Bloch exponent, but the Bloch equation remains valid.

Abstract

Nanosheets of nickel with thickness equal to 0.6 nm have been grown within the interlayer spaces of Na-4 mica. The sheets are made up of percolative clusters of nanodisks. Magnetization characteristics indicate a superparamagnetic behavior with a blocking temperature of 428 K.The magnetic anisotropy constant as extracted from the coercivity data has been found to be higher than that of bulk nickel by two orders of magnitude. This is ascribed to a large aspect ratio of the nickel nanophase. The Bloch exponent is also found to be considerably different from that of bulk nickel because of a size effect. The Bloch Equation is still found to be valid for the two dimensional structures.