Magneto-optical recording

Tsunashima, S.

doi:10.1088/0022-3727/34/17/201

“…Amorphous alloys of rare earth-transition metals have been extensively studied in the 1970's 1) and have found technological application as storage and read-out layers in magneto-optical disks 2) . The interest for this class of materials was renewed with the recent discovery that, in GdFeCo ferrimagnetic amorphous alloys, a single femtosecond circularly polarized laser pulse can reverse the magnetization without the need of applying any external magnetic field 3) .…”

Section: Introductionmentioning

confidence: 99%

Nanostructuring of GdFeCo Thin Films for Laser Induced Magnetization Switching

Guyader

¹

,

Moussaoui

²

,

Mengotti

³

et al. 2012

View full text Add to dashboard Cite

The effect of structuring GdFeCo thin films has been investigated in view of laser induced magnetic recording applications. It is found that patterning the substrate via electron beam lithography combined with reactive ion etching before the actual magnetic layer deposition can produce a significant magnetic de-coupling between the obtained structures and their immediate magnetic surrounding. However, upon laser heating, dipolar coupling with this surrounding is found to determine completely the magnetization orientation of the structures, a situation which could be problematic for laser induced recording applications. An alternative structuring approach, based on a lift-off technique of the magnetic layer, is immune to this problem since no magnetic surrounding remains.

show abstract

“…Lanthanide (Ln) doped or concentrated materials are used in a diversity of applications such as lasers, light emitting diodes, phosphors or scintillators [1], and are being considered for future applications based on spintronics [2] or high density optical or magnetic data storage [3]. Besides application, Ln materials are at the focal point of solid state research into a variety of fundamental phenomena such as valence fluctuations [4], semi-conductor to metal phase transitions [5] or giant magneto resistance [6].…”

Section: Introductionmentioning

confidence: 99%

Systematic and material independent variation of electrical, optical, and chemical properties of Ln-materials over the Ln-series (Ln=La,Ce,Pr,..,Lu)

Kolk

¹

,

Dorenbos

²

2007

View full text Add to dashboard Cite

A model is presented that successfully predicts electro-optical properties of Lanthanide materials, irrespective whether these materials are inorganic or organic, diluted or concentrated, metallic, semi-conducting or insulating. The model is firmly based on recent experimental data revealing that the variation in 4f and 5d energies relative to the valence band over the Ln series (La, Ce, Pr,.. ,Lu) is universal. Application to LnS and the oxides LnO, Ln 2 O 3 and LnO 2 demonstrates its potential by correctly predicting the ground state electron configuration, metallic, insulating or semi-conducting behavior, Ln ion valence state and band-gap of these model Ln systems. IntroductionLanthanide (Ln) doped or concentrated materials are used in a diversity of applications such as lasers, light emitting diodes, phosphors or scintillators [1], and are being considered for future applications based on spintronics [2] or high density optical or magnetic data storage [3]. Besides application, Ln materials are at the focal point of solid state research into a variety of fundamental phenomena such as valence fluctuations [4], semi-conductor to metal phase transitions [5] or giant magneto resistance [6]. The wide variety of electrical, optical and magnetic behavior of Ln materials in both diluted and concentrated systems is to a large extend controlled by the energy of the 5d states relative to the 4f states. In wide band-gap insulators 5d states are well above the 4f ground state, and many luminescent materials are based on emissive transitions within the rich energy level structure of the 4f configuration [7]. When the lowest energy 5d states are close to, but still above, the 4f ground state, semi-conducting behavior dominates and ferromagnetic ordering with pronounced magneto-resistance effects has been observed [6]. When the lowest energy 5d state becomes resonant with the 4f ground state, Ln materials become critically sensitive to internal or external perturbations like pressure that can trigger a ground state configuration change from 4f n 5d 0 to 4f n-1 5d 1 resulting in a semi-conductor to metal phase transition and a non integer Ln ion valence state fluctuating in time [8]. Finally, integer Ln valence state and metallic behavior is observed when the lowest energy 5d state is well below the lowest energy 4f state.Clearly, any model that has the pretension to explain and predict Ln material properties will need to consider the basic electronic structure, that is the ordering in energy of (i) the lowest energy Ln 4f state and (ii) the lowest energy 5d state, that is, the bottom of the 5d-derived conduction band (CB). In this report, we present experimental data convincingly demonstrating that the variation in energy of the 4f and 5d states relative to the valence band (VB) over the Ln series (La, Ce, Pr,.., Lu) in a particular material is independent of Ln valence state or concentration, and that

show abstract

“…Lanthanide (Ln) doped or concentrated materials are used in a diversity of applications such as lasers, light emitting diodes, phosphors or scintillators [1], and are being considered for future applications based on spintronics [2] or high density optical or magnetic data storage [3]. Besides application, Ln materials are at the focal point of solid state research into a variety of fundamental phenomena such as valence fluctuations [4], semi-conductor to metal phase transitions [5] or giant magneto resistance [6].…”

Section: Introductionmentioning

confidence: 99%

Systematic and Material Independent Variation of Electrical, Optical, and Chemical Properties of Ln Materials over the Ln Series (Ln: La, Ce, Pr, ..., Lu).

Kolk

¹

,

Dorenbos

²

2006

ChemInform

0

View full text Add to dashboard Cite

A model is presented that successfully predicts electro-optical properties of Lanthanide materials, irrespective whether these materials are inorganic or organic, diluted or concentrated, metallic, semi-conducting or insulating. The model is firmly based on recent experimental data revealing that the variation in 4f and 5d energies relative to the valence band over the Ln series (La, Ce, Pr,.. ,Lu) is universal. Application to LnS and the oxides LnO, Ln 2 O 3 and LnO 2 demonstrates its potential by correctly predicting the ground state electron configuration, metallic, insulating or semi-conducting behavior, Ln ion valence state and band-gap of these model Ln systems. IntroductionLanthanide (Ln) doped or concentrated materials are used in a diversity of applications such as lasers, light emitting diodes, phosphors or scintillators [1], and are being considered for future applications based on spintronics [2] or high density optical or magnetic data storage [3]. Besides application, Ln materials are at the focal point of solid state research into a variety of fundamental phenomena such as valence fluctuations [4], semi-conductor to metal phase transitions [5] or giant magneto resistance [6]. The wide variety of electrical, optical and magnetic behavior of Ln materials in both diluted and concentrated systems is to a large extend controlled by the energy of the 5d states relative to the 4f states. In wide band-gap insulators 5d states are well above the 4f ground state, and many luminescent materials are based on emissive transitions within the rich energy level structure of the 4f configuration [7]. When the lowest energy 5d states are close to, but still above, the 4f ground state, semi-conducting behavior dominates and ferromagnetic ordering with pronounced magneto-resistance effects has been observed [6]. When the lowest energy 5d state becomes resonant with the 4f ground state, Ln materials become critically sensitive to internal or external perturbations like pressure that can trigger a ground state configuration change from 4f n 5d 0 to 4f n-1 5d 1 resulting in a semi-conductor to metal phase transition and a non integer Ln ion valence state fluctuating in time [8]. Finally, integer Ln valence state and metallic behavior is observed when the lowest energy 5d state is well below the lowest energy 4f state.Clearly, any model that has the pretension to explain and predict Ln material properties will need to consider the basic electronic structure, that is the ordering in energy of (i) the lowest energy Ln 4f state and (ii) the lowest energy 5d state, that is, the bottom of the 5d-derived conduction band (CB). In this report, we present experimental data convincingly demonstrating that the variation in energy of the 4f and 5d states relative to the valence band (VB) over the Ln series (La, Ce, Pr,.., Lu) in a particular material is independent of Ln valence state or concentration, and that

show abstract

Magneto-optical recording

Cited by 105 publications

References 38 publications

Nanostructuring of GdFeCo Thin Films for Laser Induced Magnetization Switching

Nanostructuring of GdFeCo Thin Films for Laser Induced Magnetization Switching

Systematic and material independent variation of electrical, optical, and chemical properties of Ln-materials over the Ln-series (Ln=La,Ce,Pr,..,Lu)

Systematic and Material Independent Variation of Electrical, Optical, and Chemical Properties of Ln Materials over the Ln Series (Ln: La, Ce, Pr, ..., Lu).

Contact Info

Product

Resources

About