HAMR Media Mg Trapping Layer Mitigates NFT Damage
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) systems, magnesium (Mg) migration from the seed layer to the disk surface and slider can cause damage to the near-field transducer (NFT), leading to reliability issues and potential disk failure due to the formation of SiMgO compounds with lower thermal conductivity, which can accumulate thermal stress and break off during operation.
Innovation Solution
A magnesium trapping layer comprising oxides such as TiO, TiO2, SiO, BaO, HfO, ZrO, MgTiO, MgTiO2, MgSiO, MgBaO, MgHfO, or MgZrO is introduced to mitigate Mg migration, reacting with dissociated Mg before it reaches the SiO2 of the NFT, thereby reducing the formation of SiMgO and minimizing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a MgO seed layer is used in HAMR media to enable high-temperature recording, then recording performance is improved, but Mg migration to the slider occurs causing reliability issues
Solution Approach 1:
A Mg trapping layer comprising TiO2, SiO2, or other oxides is introduced as an intermediary layer between the MgO seed layer and the magnetic recording layer. This trapping layer has a lower bond dissociation energy than SiO2, causing it to preferentially react with dissociated Mg atoms and prevent their migration to the slider surface, thus protecting the NFT from Mg-related damage.
Solution Approach 2:
The harmful Mg migration is converted into a beneficial effect by designing a trapping layer that intentionally captures Mg atoms. The Mg atoms that would otherwise damage the NFT are instead trapped in the oxide layer through controlled chemical reactions, transforming a reliability hazard into a protective mechanism.
2Productivity
If high temperatures are applied during HAMR writing to achieve higher areal density, then recording capability is improved, but thermal stress and component reliability deteriorate
Solution Approach 1:
The bond dissociation energy parameter of the trapping layer oxide is specifically selected to be lower than that of SiO2 (e.g., TiO2 at 1.08 eV vs SiO2 at 1.8 eV). This parameter change ensures that at HAMR operating temperatures, the trapping layer oxide preferentially reacts with Mg atoms before they can reach the slider, thereby enabling high-temperature recording while protecting components.
3Reliability
If Mg migrates to the disk surface and reacts with SiO2 on the NFT, then SiMgO compounds are formed, but thermal conductivity decreases causing thermal stress
Solution Approach 1:
The Mg trapping layer is positioned and designed to perform preliminary action by capturing Mg atoms as they dissociate from the seed layer, before these atoms can migrate to the disk surface and react with SiO2 on the NFT. This preemptive trapping prevents the formation of SiMgO compounds and maintains the thermal conductivity of the SiO2 layer.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The Mg trapping layer effectively reduces Mg migration, enhancing the reliability of the NFT and extending the lifespan of HAMR disk drives by preventing adverse reactions with SiO2 and maintaining thermal conductivity, thus improving the operational stability of HAMR systems.
Implementation Method 1
The Mg trapping layer comprises an oxide selected from the group consisting of TiO, TiO2, SiO, BaO, HfO, ZrO, MgTiO, MgTiO2, MgSiO, MgBaO, MgHfO, MgZrO, and combinations thereof. The Mg trapping layer is configured to mitigate Mg migration from the seed layer to a surface of the HAMR medium above the magnetic recording layer.
Implementation Method 2
The Mg trapping layer comprises a first compound having a first bond dissociation energy that is lower than a second bond dissociation energy of SiO2
Data Source
AI summary
Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium that has a magnesium (Mg) trapping layer that is configured to mitigate Mg migration in the HAMR medium so as to prevent near field transducer (NFT) damage caused by dissociated Mg reacting with a compound used in the NFT. In one example, the HAMR medium can include a substrate, a seed layer on the substrate and including MgO, a magnetic recording layer on the seed layer, and a Mg trapping layer on the substrate and configured to mitigate Mg migration from the seed layer to a surface of the HAMR medium above the magnetic recording layer.