Ulrichs, Henning

[["dc.bibliographiccitation.artnumber","142116"],["dc.bibliographiccitation.issue","14"],["dc.bibliographiccitation.journal","Journal of Applied Physics"],["dc.bibliographiccitation.volume","120"],["dc.contributor.author","Ulrichs, Henning"],["dc.contributor.author","Meyer, Dennis"],["dc.contributor.author","Mueller, Kai-Markus"],["dc.contributor.author","Wittrock, Steffen"],["dc.contributor.author","Mansurova, Maria"],["dc.contributor.author","Walowski, Jakob"],["dc.contributor.author","Muenzenberg, Markus G."],["dc.date.accessioned","2018-11-07T10:07:02Z"],["dc.date.available","2018-11-07T10:07:02Z"],["dc.date.issued","2016"],["dc.description.abstract","In this article, we present the observation of coherent elastic dynamics in a nano-scale phononic superlattice, which consists of only 4 bilayers. We demonstrate how ultra-short light pulses with a length of 40 fs can be utilized to excite a coherent elastic wave at 0.535 THz, which persist over about 20 ps. In later steps of the elastic dynamics, modes with frequency of 1.7 THz and above appear. All these modes are related to acoustic band gaps. Thus, the periodicity strongly manifests in the wave physics, although the system under investigation has only a small number of spatial periods. To further illustrate this, we show how by breaking the translational invariance of the superlattice, these features can be suppressed. Discussed in terms of phonon blocking and radiation, we elucidate in how far our structures can be considered as useful building blocks for phononic devices. Published by AIP Publishing."],["dc.description.sponsorship","DFG, within the CRC [1073]"],["dc.identifier.doi","10.1063/1.4961978"],["dc.identifier.isi","000386535400018"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39208"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area A | A02 Verständnis und Manipulation von Dissipationskanälen des Energietransports"],["dc.relation.issn","1089-7550"],["dc.relation.issn","0021-8979"],["dc.title","THz elastic dynamics in finite-size CoFeB-MgO phononic superlattices"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","107"],["dc.bibliographiccitation.issue","4-5"],["dc.bibliographiccitation.journal","Physics Reports"],["dc.bibliographiccitation.lastpage","136"],["dc.bibliographiccitation.volume","507"],["dc.contributor.author","Lenk, Benjamin"],["dc.contributor.author","Ulrichs, Henning"],["dc.contributor.author","Garbs, F."],["dc.contributor.author","Muenzenberg, Markus G."],["dc.date.accessioned","2018-11-07T08:50:55Z"],["dc.date.available","2018-11-07T08:50:55Z"],["dc.date.issued","2011"],["dc.description.abstract","Novel material properties can be realized by designing waves' dispersion relations in artificial crystals. The crystal's structural length scales may range from nano- (light) up to centimeters (sound waves). Because of their emergent properties these materials are called metamaterials. Different to photonics, where the dielectric constant dominantly determines the index of refraction, in a ferromagnet the spin-wave index of refraction can be dramatically changed already by the magnetization direction. This allows a different flexibility in realizing dynamic wave guides or spin-wave switches. The present review will give an introduction into the novel functionalities of spin-wave devices, concepts for spin-wave based computing and magnonic crystals. The parameters of the magnetic metamaterials are adjusted to the spin-wave k-vector such that the magnonic band structure is designed. However, already the elementary building block of an antidot lattice, the singular hole, owns a strongly varying internal potential determined by its magnetic dipole field and a localization of spin-wave modes. Photo-magnonics reveal a way to investigate the control over the interplay between localization and delocalization of the spin-wave modes using femtosecond lasers, which is a major focus of this review. We will discuss the crucial parameters to realize free Bloch states and how, by contrast, a controlled localization might allow us to gradually turn on and manipulate spin-wave interactions in spin-wave based devices in the future. (C) 2011 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.physrep.2011.06.003"],["dc.identifier.isi","000297779300001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21804"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1873-6270"],["dc.relation.issn","0370-1573"],["dc.title","The building blocks of magnonics"],["dc.type","review"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","092506"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Applied Physics Letters"],["dc.bibliographiccitation.volume","97"],["dc.contributor.author","Ulrichs, Henning"],["dc.contributor.author","Lenk, Benjamin"],["dc.contributor.author","Muenzenberg, Markus G."],["dc.date.accessioned","2018-11-07T08:40:15Z"],["dc.date.available","2018-11-07T08:40:15Z"],["dc.date.issued","2010"],["dc.description.abstract","In this paper time-resolved magneto-optical Kerr effect experiments on structured CoFeB films are presented. The geometries considered are two dimensional square lattices of micrometer-sized antidots, fabricated by a focused ion beam. The spin-wave spectra of these magnonic crystals show a precessional mode, which can be related to a Bloch state at the zone boundary. Additionally, another magnetic mode of different nature appears, whose frequency displays no dependence on the externally applied magnetic field. These findings are interpreted as delocalized and localized modes, respectively. (C) 2010 American Institute of Physics. [doi :10.1063/1.3483136]"],["dc.identifier.doi","10.1063/1.3483136"],["dc.identifier.isi","000282187200044"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/19184"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Inst Physics"],["dc.relation.issn","0003-6951"],["dc.title","Magnonic spin-wave modes in CoFeB antidot lattices"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","71"],["dc.bibliographiccitation.lastpage","81"],["dc.bibliographiccitation.seriesnr","125"],["dc.contributor.author","Lenk, Benjamin"],["dc.contributor.author","Garbs, Fabian"],["dc.contributor.author","Ulrichs, Henning"],["dc.contributor.author","Abeling, Nils O."],["dc.contributor.author","Muenzenberg, Markus G."],["dc.date.accessioned","2018-11-07T09:29:48Z"],["dc.date.available","2018-11-07T09:29:48Z"],["dc.date.issued","2013"],["dc.description.abstract","In the framework of magnonics, all-optical femtosecond laser experiments are used to study spin waves and their relaxation paths. Magnonic crystal structures based on antidots allow the control over the spin-wave modes. In these two-dimensional magnetic metamaterials with periodicities in the wave-length range of dipolar spin waves, the spin-wave bands and dispersion are modified. Hence, a specific selection of spin-wave modes excited by laser pulses is possible. Different to photonics, the modes depend strongly on the strength of the magnetostatic potential at around each antidot site - the dipolar field. While this may lead to a mode localization, also for filling fractions around or below 10 %, Bloch states are found in low damping ferromagnetic metals. In this chapter, an overview of these mechanisms is given and the connection to spin-wave band spectra calculated from an analytical model is established. Namely, the plane-wave method yields flattened bands as well as band gaps at the antidot lattice Brillouin zone boundary."],["dc.identifier.doi","10.1007/978-3-642-30247-3_6"],["dc.identifier.isi","000321718800007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/31138"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","Berlin"],["dc.relation.crisseries","Topics in Applied Physics"],["dc.relation.isbn","978-3-642-30246-6"],["dc.relation.ispartof","MAGNONICS: FROM FUNDAMENTALS TO APPLICATIONS"],["dc.relation.ispartofseries","Topics in Applied Physics; 125"],["dc.relation.issn","0303-4216"],["dc.title","Photo-Magnonics"],["dc.type","review"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","073701"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Journal of Applied Physics"],["dc.bibliographiccitation.volume","105"],["dc.contributor.author","Eilers, Gerrit"],["dc.contributor.author","Ulrichs, Henning"],["dc.contributor.author","Muenzenberg, Markus G."],["dc.contributor.author","Thomas, Andy"],["dc.contributor.author","Thiel, Karsten"],["dc.contributor.author","Seibt, Michael"],["dc.date.accessioned","2018-11-07T08:31:10Z"],["dc.date.available","2018-11-07T08:31:10Z"],["dc.date.issued","2009"],["dc.description.abstract","The amorphous (a-) CoFeB/crystalline (c-) MgO based tunneling system interface has been studied by means of quantitative high resolution transmission electron microscopy from atomic to micrometer length scales with increasing annealing temperatures. On the micron scale an irregular nucleation is found. On the atomic scale a long-range order is induced by the MgO interface, explaining the high tunnel magnetoresistance values > 100% even for not fully crystallized CoFeB/MgO/CoFeB tunnel junctions. (C) 2009 American Institute of Physics. [DOI:10.1063/1.3100044]"],["dc.identifier.doi","10.1063/1.3100044"],["dc.identifier.isi","000266633500032"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/17062"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Inst Physics"],["dc.relation.issn","1089-7550"],["dc.relation.issn","0021-8979"],["dc.title","Long-range order on the atomic scale induced at CoFeB/MgO interfaces"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","11"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Applied Physics A"],["dc.bibliographiccitation.lastpage","18"],["dc.bibliographiccitation.volume","119"],["dc.contributor.author","Doering, F."],["dc.contributor.author","Eberl, Christian"],["dc.contributor.author","Schlenkrich, Susanne"],["dc.contributor.author","Schlenkrich, Felix"],["dc.contributor.author","Hoffmann, S."],["dc.contributor.author","Liese, Tobias"],["dc.contributor.author","Krebs, Hans-Ulrich"],["dc.contributor.author","Pisana, S."],["dc.contributor.author","Santos, T."],["dc.contributor.author","Schuhmann, Henning"],["dc.contributor.author","Seibt, M."],["dc.contributor.author","Mansurova, M."],["dc.contributor.author","Ulrichs, Henning"],["dc.contributor.author","Zbarsky, Vladyslav"],["dc.contributor.author","Muenzenberg, Markus G."],["dc.date.accessioned","2018-11-07T09:59:19Z"],["dc.date.available","2018-11-07T09:59:19Z"],["dc.date.issued","2015"],["dc.description.abstract","An efficient way for minimizing phonon thermal conductivity in solids is to nanostructure them by means of reduced phonon mean free path, phonon scattering and phonon reflection at interfaces. A sophisticated approach toward this lies in the fabrication of thin multilayer films of different materials. In this paper, we show by femtosecond-pump-probe reflectivity measurements that in different multilayer systems with varying acoustic mismatch (consisting of metals, semiconductors, oxides and polymers), oscillations due to phonon localization can be observed. For the growth of multilayer films with well-defined layer thicknesses, we used magnetron sputtering, evaporation and pulsed laser deposition. By altering the material combinations and reducing the layer thicknesses down to 3 nm, we observed different mechanisms of phonon blocking, reaching in the frequency regime up to 360 GHz."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft [SFB 1073]"],["dc.identifier.doi","10.1007/s00339-015-9037-z"],["dc.identifier.isi","000351171600002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/37563"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area A | A02 Verständnis und Manipulation von Dissipationskanälen des Energietransports"],["dc.relation.issn","1432-0630"],["dc.relation.issn","0947-8396"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Phonon localization in ultrathin layered structures"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]