24 research outputs found
Laser-induced Precession of Magnetization in GaMnAs
We report on the photo-induced precession of the ferromagnetically coupled Mn
spins in (Ga,Mn)As, which is observed even with no external magnetic field
applied. We concentrate on various experimental aspects of the time-resolved
magneto-optical Kerr effect (TR-MOKE) technique that can be used to clarify the
origin of the detected signals. We show that the measured data typically
consist of several different contributions, among which only the oscillatory
signal is directly connected with the ferromagnetic order in the sample.Comment: 4 pages, 5 figure
Implementation conditions for diet and physical activity interventions and policies : an umbrella review
BACKGROUND: This umbrella review aimed at identifying evidence-based conditions important for successful implementation of interventions and policies promoting a healthy diet, physical activity (PA), and a reduction in sedentary behaviors (SB). In particular, we examined if the implementation conditions identified were intervention-specific or policy-specific. This study was undertaken as part of the DEterminants of DIet and Physical Activity (DEDIPAC) Knowledge Hub, a joint action as part of the European Joint Programming Initiative a Healthy Diet for a Healthy Life.
METHODS: A systematic review of reviews and stakeholder documents was conducted. Data from nine scientific literature databases were analyzed (95 documents met the inclusion criteria). Additionally, published documentation of eight major stakeholders (e.g., World Health Organization) were systematically searched (17 documents met the inclusion criteria). The RE-AIM framework was used to categorize elicited conditions. Across the implementation conditions 25 % were identified in at least four documents and were subsequently classified as having obtained sufficient support.
RESULTS: We identified 312 potential conditions relevant for successful implementation; 83 of these received sufficient support. Using the RE-AIM framework eight implementation conditions that obtained support referred to the reach in the target population; five addressed efficacy of implementation processes; 24 concerned adoption by the target staff, setting, or institutions; 43 referred to consistency, costs, and adaptations made in the implementation process; three addressed maintenance of effects over time. The vast majority of implementation conditions (87.9 %; 73 of 83) were supported by documents referring to both interventions and policies. There were seven policy-specific implementation conditions, which focused on increasing complexities of coexisting policies/legal instruments and their consequences for implementation, as well as politicians' collaboration in implementation.
CONCLUSIONS: The use of the proposed list of 83 conditions for successful implementation may enhance the implementation of interventions and policies which pursue identification of the most successful actions aimed at improving diet, PA and reducing SB
Light-induced magnetization precession in GaMnAs
We report dynamics of the transient polar Kerr rotation (KR) and of the
transient reflectivity induced by femtosecond laser pulses in ferromagnetic
(Ga,Mn)As with no external magnetic field applied. It is shown that the
measured KR signal consist of several different contributions, among which only
the oscillatory signal is directly connected with the ferromagnetic order in
(Ga,Mn)As. The origin of the light-induced magnetization precession is
discussed and the magnetization precession damping (Gilbert damping) is found
to be strongly influenced by annealing of the sample.Comment: 6 pages, 4 figures. accepted in Applied Physics Letter
Optical determination of the NĂ©el vector in a CuMnAs thin-film antiferromagnet
Recent breakthroughs in electrical detection and manipulation of antiferromagnets have opened a new avenue in the research of non-volatile spintronic devices.1-10 Antiparallel spin sublattices in antiferromagnets, producing zero dipolar fields, lead to the insensitivity to magnetic field perturbations, multi-level stability, ultrafast spin dynamics and other favorable characteristics which may find utility in fields ranging from magnetic memories to optical signal processing. However, the absence of a net magnetic moment and the ultra-short magnetization dynamics timescales make antiferromagnets notoriously difficult to study by common magnetometers or magnetic resonance techniques. In this paper we demonstrate the experimental determination of the NĂ©el vector in a thin film of antiferromagnetic CuMnAs9,10 which is the prominent material used in the first realization of antiferromagnetic memory chips.10 We employ a femtosecond pump-probe magneto-optical experiment based on magnetic linear dichroism. This table-top optical method is considerably more accessible than the traditionally employed large scale facility techniques like neutron diffraction11 and Xray magnetic dichroism measurements.12-14 This optical technique allows an unambiguous direct determination of the NĂ©el vector orientation in thin antiferromagnetic films utilized in devices directly from measured data without fitting to a theoretical model