Nanocluster building blocks of artificial square spin ice: Stray-field studies of thermal dynamics

Abstract

We present measurements of the thermal dynamics of a Co-based single building block of an artificial square spin ice fabricated by focused electron-beam-induced deposition. We employ micro-Hall magnetometry, an ultra-sensitive tool to study the stray field emanating from magnetic nanostructures, as a new technique to access the dynamical properties during the magnetization reversal of the spin-ice nanocluster. The obtained hysteresis loop exhibits distinct steps, displaying a reduction of their “coercive field” with increasing temperature. Therefore, thermally unstable states could be repetitively prepared by relatively simple temperature and field protocols allowing one to investigate the statistics of their switching behavior within experimentally accessible timescales. For a selected switching event, we find a strong reduction of the so-prepared states' “survival time” with increasing temperature and magnetic field. Besides the possibility to control the lifetime of selected switching events at will, we find evidence for a more complex behavior caused by the special spin ice arrangement of the macrospins, i.e., that the magnetic reversal statistically follows distinct “paths” most likely driven by thermal perturbation.

The rational design of a Au(I) precursor for focused electron beam induced deposition

“…FEBIP is an advanced and well-established technique for modifying samples on the nanometer scale. Depending on the precursor type it is possible to deposit metals (e.g., Co [ 7 – 8 ], Fe [ 9 – 10 ], Au [ 11 – 12 ], Pt [ 13 – 14 ]), insulators (e.g., SiO x [ 15 ]) and alloys (e.g., AuAg and AuPt [ 4 ]). Materials such as Si, SiO 2 , Si 3 N 4 , Cr, Ti and TaN can be etched [ 16 ].…”

Magnetic Stray Field Detection as Guidance for Electronic Transport Measurements in the B-T Phase Diagram of MnSi

“…Micro-Hall magnetometry already has proven to be a versatile tool allowing for high-resolution studies of the magnetization reversal of isolated nanostructures [17][18][19]. Therefore, in addition to the detection of local magnetic entities, as e.g.…”

“…for studying their dynamical transport and magnetic properties) are conceivable. Also, since the combination of micro-Hall magnetometry with direct-write magnetic nanostructures using focused electron beam induced deposition has proven to be extremely fruitful in the past [17][18][19], simultaneous magnetic and transport studies of 2D and 3D nanostructures become possible. A1 represents the transition entering the skyrmion phase, while B A2 marks the upper phase boundary (designations in accordance with [14]).…”

Models of the energy landscape for an element of shakti spin ice

“…The magnetic ordering of kagome spin ice building blocks has been extensively studied both for demagnetized states [8] and thermally relaxed ground state ordering [11] as well as thermally induced dynamics [12]. For square ice building blocks, thermal effects have been directly measured through their stray field [13,14]. Studies of the energy landscape and ordering of shakti lattice building blocks containing elements of two different island sizes have previously not been reported in the literature.…”