Sergio Puebla is a PhD researcher who is becoming a doctor these days. On July, 29th, he is defending the work he has been doing last years under the direction of Andrés Castellanos and Carmen Munuera. His thesis, entitled 'Free-standing Transition Metal Oxide Thin Films: From Properties to Application' is about "very thin materials", he explains to a non-scientific audience. "I start making the wax to rocks that delaminate and separate them in very thin layers to build electronic devices and be able to inspect their optical and electronic properties", he adds.