Anisotropic magnetism of graphite irradiated with medium-energy hydrogen and helium ions

被引：40

作者：

Makarova, T. L. ^{[1
,2
]}

Shelankov, A. L. ^{[1
,2
]}

Serenkov, I. T. ^{[2
]}

Sakharov, V. I. ^{[2
]}

Boukhvalov, D. W. ^{[3
]}

机构：

[1] Umea Univ, Dept Phys, Umea, Sweden

[2] RAS, AF Ioffe Physicotech Inst, St Petersburg, Russia

[3] Natl Inst Mat Sci, Computat Mat Sci Ctr, Tsukuba, Ibaraki 3050047, Japan

来源：

PHYSICAL REVIEW B | 2011年 / 83卷 / 08期

基金：

瑞典研究理事会;

关键词：

ORIENTED PYROLYTIC-GRAPHITE; PROTON IRRADIATION; IMPLANTED GRAPHITE; CARBON; GRAPHENE; FERROMAGNETISM; MICROSCOPY; CASCADES; DEFECTS; SURFACE;

D O I：

10.1103/PhysRevB.83.085417

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We have studied the changes in the magnetic behavior of highly oriented pyrolytic graphite (HOPG) samples subjected to medium-energy proton and helium irradiation. The variations of the ferromagneticlike magnetization curves with the irradiation dose have been studied for two configurations: magnetic fields parallel and perpendicular to graphitic planes. For high irradiation doses, the values of magnetization at saturation are close for both geometries. At low irradiation fluences an orientationally dependent magnetic response is obtained. Directional dependence of magnetization indicates that the magnetism in irradiated graphite is triggered by vertically aligned intrinsic carbon defects induced by irradiation. This physical picture has been verified by the observation of a local stray field near linear defects by means of magnetic force microscopy. Similar results obtained with hydrogen and helium ions confirm that the chemical nature of projectiles is not crucial for formation of ferromagnetic order in oriented graphite. The dependence of induced magnetic moment versus irradiation dose shows a maximum; the optimal dose is an order of magnitude less for helium ions than for protons, being in line with simulations showing that He+ generates 8 times more defects than H+. Raman studies indicate that the degradation of magnetic ordering at large irradiation doses occurs much earlier than graphite amorphization but coincides with the destruction of graphene sheet stacking.

引用

页数：8