Weak ferromagnetism of La_{1.99}Sr_{0.01}CuO_4 thin films: evidence for removal of corrugation in CuO_2 plane by epitaxial strain

The weak ferromagnetism of La_{1.99}Sr_{0.01}CuO_4 epitaxial thin films is investigated using magnetoresistance measurement. While a steplike negative magnetoresistance associated with the weak ferromagnetic transition is clearly observed in the films grown on YAlO_3(001), it is notably suppressed in the films grown on SrTiO_3(100) and (LaAlO_3)_{0.3}(SrAl_{0.5}Ta_{0.5}O_3)_{0.7}(100), and almost disappears in films grown on LaSrAlO_4(001). The strong suppression of the steplike magnetoresistance provides evidence that the CuO_2 planes are much less corrugated in thin films grown on tetragonal substrates, particularly on LaSrAlO_4(001), than in bulk crystals.Comment: 6 pages, 6 figures, to be published in Physical Review

The First Born Burden

Being the first born of a family entails inherent responsibilities. Sociologists, psychologists and economists have long argued that the first born's receive differentiated treatment within the household. This paper tests and quantifies the existence of a disproportionate workload over the oldest child in poor households: we call it the first born burden. We are concerned with the determinants of such work burden, and we analyze how access to basic infrastructure could release children from work. The empirical results for rural areas in Ghana confirm a systematic selection of first born's to work. Although access to infrastructure may not reallocate evenly the workload among siblings, it indeed relaxes the children's time constraints. --child labor,time allocation,birth order,infrastructure,water