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Title: Fundamental limits in heat-assisted magnetic recording and methods to overcome it with exchange spring structures

The switching probability of magnetic elements for heat-assisted recording with pulsed laser heating was investigated. It was found that FePt elements with a diameter of 5 nm and a height of 10 nm show, at a field of 0.5 T, thermally written-in errors of 12%, which is significantly too large for bit-patterned magnetic recording. Thermally written-in errors can be decreased if larger-head fields are applied. However, larger fields lead to an increase in the fundamental thermal jitter. This leads to a dilemma between thermally written-in errors and fundamental thermal jitter. This dilemma can be partly relaxed by increasing the thickness of the FePt film up to 30 nm. For realistic head fields, it is found that the fundamental thermal jitter is in the same order of magnitude of the fundamental thermal jitter in conventional recording, which is about 0.5–0.8 nm. Composite structures consisting of high Curie top layer and FePt as a hard magnetic storage layer can reduce the thermally written-in errors to be smaller than 10{sup −4} if the damping constant is increased in the soft layer. Large damping may be realized by doping with rare earth elements. Similar to single FePt grains in composite structure, an increase of switching probability is sacrificed bymore » an increase of thermal jitter. Structures utilizing first-order phase transitions breaking the thermal jitter and writability dilemma are discussed.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ; ;  [2]
  1. Doppler Laboratory, Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna (Austria)
  2. Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna (Austria)
  3. (Austria)
Publication Date:
OSTI Identifier:
22402918
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 16; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DAMPING; ELECTROMAGNETIC PULSES; HEAT; INTERMETALLIC COMPOUNDS; IRON; LASER-RADIATION HEATING; LAYERS; PHASE TRANSFORMATIONS; PLATINUM; PROBABILITY; RARE EARTHS; THICKNESS; THIN FILMS